diff --git a/lib/src/bindings/annotated.dart b/lib/src/bindings/annotated.dart
index 74176af..bb885ab 100644
--- a/lib/src/bindings/annotated.dart
+++ b/lib/src/bindings/annotated.dart
@@ -3,7 +3,6 @@ import 'dart:ffi';
 import 'package:ffi/ffi.dart';
 import 'package:libgit2dart/src/bindings/libgit2_bindings.dart';
 import 'package:libgit2dart/src/error.dart';
-import 'package:libgit2dart/src/extensions.dart';
 import 'package:libgit2dart/src/util.dart';
 
 /// Creates an annotated commit from the given commit id. The returned
@@ -77,7 +76,7 @@ Pointer<git_annotated_commit> fromRevSpec({
   required String revspec,
 }) {
   final out = calloc<Pointer<git_annotated_commit>>();
-  final revspecC = revspec.toChar();
+  final revspecC = revspec.toNativeUtf8().cast<Char>();
   final error = libgit2.git_annotated_commit_from_revspec(
     out,
     repoPointer,
@@ -107,8 +106,8 @@ Pointer<git_annotated_commit> fromFetchHead({
   required Pointer<git_oid> oid,
 }) {
   final out = calloc<Pointer<git_annotated_commit>>();
-  final branchNameC = branchName.toChar();
-  final remoteUrlC = remoteUrl.toChar();
+  final branchNameC = branchName.toNativeUtf8().cast<Char>();
+  final remoteUrlC = remoteUrl.toNativeUtf8().cast<Char>();
   final error = libgit2.git_annotated_commit_from_fetchhead(
     out,
     repoPointer,
@@ -137,7 +136,7 @@ Pointer<git_oid> oid(Pointer<git_annotated_commit> commit) =>
 /// Get the refname that the given annotated commit refers to.
 String refName(Pointer<git_annotated_commit> commit) {
   final result = libgit2.git_annotated_commit_ref(commit);
-  return result == nullptr ? '' : result.toDartString();
+  return result == nullptr ? '' : result.cast<Utf8>().toDartString();
 }
 
 /// Frees an annotated commit.
diff --git a/lib/src/bindings/attr.dart b/lib/src/bindings/attr.dart
index 1a40993..28a1a53 100644
--- a/lib/src/bindings/attr.dart
+++ b/lib/src/bindings/attr.dart
@@ -1,7 +1,6 @@
 import 'dart:ffi';
 import 'package:ffi/ffi.dart';
 import 'package:libgit2dart/src/bindings/libgit2_bindings.dart';
-import 'package:libgit2dart/src/extensions.dart';
 import 'package:libgit2dart/src/util.dart';
 
 /// Look up the value of one git attribute for path.
@@ -16,8 +15,8 @@ Object? getAttribute({
   required String name,
 }) {
   final out = calloc<Pointer<Char>>();
-  final pathC = path.toChar();
-  final nameC = name.toChar();
+  final pathC = path.toNativeUtf8().cast<Char>();
+  final nameC = name.toNativeUtf8().cast<Char>();
   libgit2.git_attr_get(out, repoPointer, flags, pathC, nameC);
 
   final result = out.value;
@@ -38,7 +37,7 @@ Object? getAttribute({
     return false;
   }
   if (attributeValue == git_attr_value_t.GIT_ATTR_VALUE_STRING) {
-    return result.toDartString();
+    return result.cast<Utf8>().toDartString();
   }
   return null;
 }
diff --git a/lib/src/bindings/blame.dart b/lib/src/bindings/blame.dart
index 7bdab62..85ad9c3 100644
--- a/lib/src/bindings/blame.dart
+++ b/lib/src/bindings/blame.dart
@@ -2,7 +2,6 @@ import 'dart:ffi';
 import 'package:ffi/ffi.dart';
 import 'package:libgit2dart/src/bindings/libgit2_bindings.dart';
 import 'package:libgit2dart/src/error.dart';
-import 'package:libgit2dart/src/extensions.dart';
 import 'package:libgit2dart/src/oid.dart';
 import 'package:libgit2dart/src/util.dart';
 
@@ -21,7 +20,7 @@ Pointer<git_blame> file({
   int? maxLine,
 }) {
   final out = calloc<Pointer<git_blame>>();
-  final pathC = path.toChar();
+  final pathC = path.toNativeUtf8().cast<Char>();
   final options = calloc<git_blame_options>();
   libgit2.git_blame_options_init(options, GIT_BLAME_OPTIONS_VERSION);
 
@@ -78,7 +77,7 @@ Pointer<git_blame> buffer({
   required String buffer,
 }) {
   final out = calloc<Pointer<git_blame>>();
-  final bufferC = buffer.toChar();
+  final bufferC = buffer.toNativeUtf8().cast<Char>();
   final error = libgit2.git_blame_buffer(
     out,
     reference,
diff --git a/lib/src/bindings/blob.dart b/lib/src/bindings/blob.dart
index 13ed1e5..191e1bf 100644
--- a/lib/src/bindings/blob.dart
+++ b/lib/src/bindings/blob.dart
@@ -4,7 +4,6 @@ import 'package:ffi/ffi.dart';
 
 import 'package:libgit2dart/src/bindings/libgit2_bindings.dart';
 import 'package:libgit2dart/src/error.dart';
-import 'package:libgit2dart/src/extensions.dart';
 import 'package:libgit2dart/src/util.dart';
 
 /// Lookup a blob object from a repository. The returned blob must be freed
@@ -85,7 +84,7 @@ Pointer<git_oid> createFromWorkdir({
   required String relativePath,
 }) {
   final out = calloc<git_oid>();
-  final relativePathC = relativePath.toChar();
+  final relativePathC = relativePath.toNativeUtf8().cast<Char>();
   final error = libgit2.git_blob_create_from_workdir(
     out,
     repoPointer,
@@ -111,7 +110,7 @@ Pointer<git_oid> createFromDisk({
   required String path,
 }) {
   final out = calloc<git_oid>();
-  final pathC = path.toChar();
+  final pathC = path.toNativeUtf8().cast<Char>();
   final error = libgit2.git_blob_create_from_disk(out, repoPointer, pathC);
 
   calloc.free(pathC);
@@ -151,7 +150,7 @@ String filterContent({
   git_oid? attributesCommit,
 }) {
   final out = calloc<git_buf>();
-  final asPathC = asPath.toChar();
+  final asPathC = asPath.toNativeUtf8().cast<Char>();
   final opts = calloc<git_blob_filter_options>();
   libgit2.git_blob_filter_options_init(opts, GIT_BLOB_FILTER_OPTIONS_VERSION);
   opts.ref.flags = flags;
@@ -163,7 +162,7 @@ String filterContent({
 
   late final String result;
   if (out.ref.ptr != nullptr) {
-    result = out.ref.ptr.toDartString(length: out.ref.size);
+    result = out.ref.ptr.cast<Utf8>().toDartString(length: out.ref.size);
   }
 
   libgit2.git_buf_dispose(out);
diff --git a/lib/src/bindings/branch.dart b/lib/src/bindings/branch.dart
index d1738c2..d5e90a8 100644
--- a/lib/src/bindings/branch.dart
+++ b/lib/src/bindings/branch.dart
@@ -5,7 +5,6 @@ import 'package:libgit2dart/libgit2dart.dart';
 import 'package:libgit2dart/src/bindings/libgit2_bindings.dart';
 import 'package:libgit2dart/src/bindings/reference.dart' as reference_bindings;
 import 'package:libgit2dart/src/error.dart';
-import 'package:libgit2dart/src/extensions.dart';
 import 'package:libgit2dart/src/util.dart';
 
 /// Return a list of branches. The returned references must be freed with
@@ -61,7 +60,7 @@ Pointer<git_reference> lookup({
   required int branchType,
 }) {
   final out = calloc<Pointer<git_reference>>();
-  final branchNameC = branchName.toChar();
+  final branchNameC = branchName.toNativeUtf8().cast<Char>();
   final error = libgit2.git_branch_lookup(
     out,
     repoPointer,
@@ -98,7 +97,7 @@ Pointer<git_reference> create({
   required bool force,
 }) {
   final out = calloc<Pointer<git_reference>>();
-  final branchNameC = branchName.toChar();
+  final branchNameC = branchName.toNativeUtf8().cast<Char>();
   final forceC = force ? 1 : 0;
   final error = libgit2.git_branch_create(
     out,
@@ -148,7 +147,7 @@ void rename({
   required bool force,
 }) {
   final out = calloc<Pointer<git_reference>>();
-  final newBranchNameC = newBranchName.toChar();
+  final newBranchNameC = newBranchName.toNativeUtf8().cast<Char>();
   final forceC = force ? 1 : 0;
   final error = libgit2.git_branch_move(
     out,
@@ -213,7 +212,7 @@ String name(Pointer<git_reference> ref) {
   if (error < 0) {
     throw LibGit2Error(libgit2.git_error_last());
   } else {
-    return result.toDartString();
+    return result.cast<Utf8>().toDartString();
   }
 }
 
@@ -230,10 +229,10 @@ String remoteName({
   required String branchName,
 }) {
   final out = calloc<git_buf>();
-  final branchNameC = branchName.toChar();
+  final branchNameC = branchName.toNativeUtf8().cast<Char>();
   final error = libgit2.git_branch_remote_name(out, repoPointer, branchNameC);
 
-  final result = out.ref.ptr.toDartString(length: out.ref.size);
+  final result = out.ref.ptr.cast<Utf8>().toDartString(length: out.ref.size);
 
   libgit2.git_buf_dispose(out);
   calloc.free(out);
@@ -282,7 +281,7 @@ void setUpstream({
   required Pointer<git_reference> branchPointer,
   required String? branchName,
 }) {
-  final branchNameC = branchName?.toChar() ?? nullptr;
+  final branchNameC = branchName?.toNativeUtf8().cast<Char>() ?? nullptr;
   final error = libgit2.git_branch_set_upstream(branchPointer, branchNameC);
 
   calloc.free(branchNameC);
@@ -304,10 +303,10 @@ String upstreamName({
   required String branchName,
 }) {
   final out = calloc<git_buf>();
-  final branchNameC = branchName.toChar();
+  final branchNameC = branchName.toNativeUtf8().cast<Char>();
   final error = libgit2.git_branch_upstream_name(out, repoPointer, branchNameC);
 
-  final result = out.ref.ptr.toDartString(length: out.ref.size);
+  final result = out.ref.ptr.cast<Utf8>().toDartString(length: out.ref.size);
 
   libgit2.git_buf_dispose(out);
   calloc.free(out);
@@ -331,14 +330,14 @@ String upstreamRemote({
   required String branchName,
 }) {
   final out = calloc<git_buf>();
-  final branchNameC = branchName.toChar();
+  final branchNameC = branchName.toNativeUtf8().cast<Char>();
   final error = libgit2.git_branch_upstream_remote(
     out,
     repoPointer,
     branchNameC,
   );
 
-  final result = out.ref.ptr.toDartString(length: out.ref.size);
+  final result = out.ref.ptr.cast<Utf8>().toDartString(length: out.ref.size);
 
   libgit2.git_buf_dispose(out);
   calloc.free(out);
@@ -362,14 +361,14 @@ String upstreamMerge({
   required String branchName,
 }) {
   final out = calloc<git_buf>();
-  final branchNameC = branchName.toChar();
+  final branchNameC = branchName.toNativeUtf8().cast<Char>();
   final error = libgit2.git_branch_upstream_merge(
     out,
     repoPointer,
     branchNameC,
   );
 
-  final result = out.ref.ptr.toDartString(length: out.ref.size);
+  final result = out.ref.ptr.cast<Utf8>().toDartString(length: out.ref.size);
 
   libgit2.git_buf_dispose(out);
   calloc.free(out);
diff --git a/lib/src/bindings/checkout.dart b/lib/src/bindings/checkout.dart
index ec139be..cc883da 100644
--- a/lib/src/bindings/checkout.dart
+++ b/lib/src/bindings/checkout.dart
@@ -3,7 +3,6 @@ import 'dart:ffi';
 import 'package:ffi/ffi.dart';
 import 'package:libgit2dart/src/bindings/libgit2_bindings.dart';
 import 'package:libgit2dart/src/error.dart';
-import 'package:libgit2dart/src/extensions.dart';
 import 'package:libgit2dart/src/util.dart';
 
 /// Updates files in the index and the working tree to match the content of the
@@ -128,13 +127,13 @@ List<Object> initOptions({
   optsC.ref.checkout_strategy = strategy;
 
   if (directory != null) {
-    optsC.ref.target_directory = directory.toChar();
+    optsC.ref.target_directory = directory.toNativeUtf8().cast<Char>();
   }
 
   var pathPointers = <Pointer<Char>>[];
   Pointer<Pointer<Char>> strArray = nullptr;
   if (paths != null) {
-    pathPointers = paths.map((e) => e.toChar()).toList();
+    pathPointers = paths.map((e) => e.toNativeUtf8().cast<Char>()).toList();
     strArray = calloc(paths.length);
     for (var i = 0; i < paths.length; i++) {
       strArray[i] = pathPointers[i];
diff --git a/lib/src/bindings/commit.dart b/lib/src/bindings/commit.dart
index f4a97c6..4a6d5cd 100644
--- a/lib/src/bindings/commit.dart
+++ b/lib/src/bindings/commit.dart
@@ -3,7 +3,6 @@ import 'dart:ffi';
 import 'package:ffi/ffi.dart';
 import 'package:libgit2dart/src/bindings/libgit2_bindings.dart';
 import 'package:libgit2dart/src/error.dart';
-import 'package:libgit2dart/src/extensions.dart';
 import 'package:libgit2dart/src/util.dart';
 
 /// Lookup a commit object from a repository. The returned commit must be
@@ -46,9 +45,10 @@ Pointer<git_oid> create({
   required List<Pointer<git_commit>> parents,
 }) {
   final out = calloc<git_oid>();
-  final updateRefC = updateRef.toChar();
-  final messageEncodingC = messageEncoding?.toChar() ?? nullptr;
-  final messageC = message.toChar();
+  final updateRefC = updateRef.toNativeUtf8().cast<Char>();
+  final messageEncodingC =
+      messageEncoding?.toNativeUtf8().cast<Char>() ?? nullptr;
+  final messageC = message.toNativeUtf8().cast<Char>();
   final parentsC = calloc<Pointer<git_commit>>(parentCount);
 
   if (parents.isNotEmpty) {
@@ -103,9 +103,10 @@ String createBuffer({
   required List<Pointer<git_commit>> parents,
 }) {
   final out = calloc<git_buf>();
-  final updateRefC = updateRef.toChar();
-  final messageEncodingC = messageEncoding?.toChar() ?? nullptr;
-  final messageC = message.toChar();
+  final updateRefC = updateRef.toNativeUtf8().cast<Char>();
+  final messageEncodingC =
+      messageEncoding?.toNativeUtf8().cast<Char>() ?? nullptr;
+  final messageC = message.toNativeUtf8().cast<Char>();
   final parentsC = calloc<Pointer<git_commit>>(parentCount);
 
   if (parents.isNotEmpty) {
@@ -128,7 +129,7 @@ String createBuffer({
     parentsC,
   );
 
-  final result = out.ref.ptr.toDartString(length: out.ref.size);
+  final result = out.ref.ptr.cast<Utf8>().toDartString(length: out.ref.size);
 
   libgit2.git_buf_dispose(out);
   calloc.free(out);
@@ -168,9 +169,10 @@ Pointer<git_oid> amend({
   required Pointer<git_tree>? treePointer,
 }) {
   final out = calloc<git_oid>();
-  final updateRefC = updateRef?.toChar() ?? nullptr;
-  final messageEncodingC = messageEncoding?.toChar() ?? nullptr;
-  final messageC = message?.toChar() ?? nullptr;
+  final updateRefC = updateRef?.toNativeUtf8().cast<Char>() ?? nullptr;
+  final messageEncodingC =
+      messageEncoding?.toNativeUtf8().cast<Char>() ?? nullptr;
+  final messageC = message?.toNativeUtf8().cast<Char>() ?? nullptr;
 
   final error = libgit2.git_commit_amend(
     out,
@@ -214,7 +216,7 @@ Pointer<git_commit> duplicate(Pointer<git_commit> source) {
 /// If the encoding header in the commit is missing UTF-8 is assumed.
 String messageEncoding(Pointer<git_commit> commit) {
   final result = libgit2.git_commit_message_encoding(commit);
-  return result == nullptr ? 'utf-8' : result.toDartString();
+  return result == nullptr ? 'utf-8' : result.cast<Utf8>().toDartString();
 }
 
 /// Get the full message of a commit.
@@ -222,7 +224,7 @@ String messageEncoding(Pointer<git_commit> commit) {
 /// The returned message will be slightly prettified by removing any potential
 /// leading newlines.
 String message(Pointer<git_commit> commit) {
-  return libgit2.git_commit_message(commit).toDartString();
+  return libgit2.git_commit_message(commit).cast<Utf8>().toDartString();
 }
 
 /// Get the short "summary" of the git commit message.
@@ -237,7 +239,7 @@ String summary(Pointer<git_commit> commit) {
   if (result == nullptr) {
     throw LibGit2Error(libgit2.git_error_last());
   } else {
-    return result.toDartString();
+    return result.cast<Utf8>().toDartString();
   }
 }
 
@@ -248,7 +250,7 @@ String summary(Pointer<git_commit> commit) {
 /// trimmed.
 String body(Pointer<git_commit> commit) {
   final result = libgit2.git_commit_body(commit);
-  return result == nullptr ? '' : result.toDartString();
+  return result == nullptr ? '' : result.cast<Utf8>().toDartString();
 }
 
 /// Get an arbitrary header field.
@@ -259,10 +261,10 @@ String headerField({
   required String field,
 }) {
   final out = calloc<git_buf>();
-  final fieldC = field.toChar();
+  final fieldC = field.toNativeUtf8().cast<Char>();
   final error = libgit2.git_commit_header_field(out, commitPointer, fieldC);
 
-  final result = out.ref.ptr.toDartString(length: out.ref.size);
+  final result = out.ref.ptr.cast<Utf8>().toDartString(length: out.ref.size);
 
   libgit2.git_buf_dispose(out);
   calloc.free(out);
diff --git a/lib/src/bindings/config.dart b/lib/src/bindings/config.dart
index 813cd4c..796e818 100644
--- a/lib/src/bindings/config.dart
+++ b/lib/src/bindings/config.dart
@@ -5,14 +5,13 @@ import 'dart:ffi';
 import 'package:ffi/ffi.dart';
 import 'package:libgit2dart/src/bindings/libgit2_bindings.dart';
 import 'package:libgit2dart/src/error.dart';
-import 'package:libgit2dart/src/extensions.dart';
 import 'package:libgit2dart/src/util.dart';
 
 /// Create a new config instance containing a single on-disk file. The returned
 /// config must be freed with [free].
 Pointer<git_config> open(String path) {
   final out = calloc<Pointer<git_config>>();
-  final pathC = path.toChar();
+  final pathC = path.toNativeUtf8().cast<Char>();
   libgit2.git_config_open_ondisk(out, pathC);
 
   calloc.free(pathC);
@@ -60,7 +59,7 @@ String findGlobal() {
   final out = calloc<git_buf>();
   final error = libgit2.git_config_find_global(out);
 
-  final result = out.ref.ptr.toDartString(length: out.ref.size);
+  final result = out.ref.ptr.cast<Utf8>().toDartString(length: out.ref.size);
 
   libgit2.git_buf_dispose(out);
   calloc.free(out);
@@ -82,7 +81,7 @@ String findSystem() {
   final out = calloc<git_buf>();
   final error = libgit2.git_config_find_system(out);
 
-  final result = out.ref.ptr.toDartString(length: out.ref.size);
+  final result = out.ref.ptr.cast<Utf8>().toDartString(length: out.ref.size);
 
   libgit2.git_buf_dispose(out);
   calloc.free(out);
@@ -108,7 +107,7 @@ String findXdg() {
   final out = calloc<git_buf>();
   final error = libgit2.git_config_find_xdg(out);
 
-  final result = out.ref.ptr.toDartString(length: out.ref.size);
+  final result = out.ref.ptr.cast<Utf8>().toDartString(length: out.ref.size);
 
   libgit2.git_buf_dispose(out);
   calloc.free(out);
@@ -146,7 +145,7 @@ Pointer<git_config_entry> getEntry({
   required String variable,
 }) {
   final out = calloc<Pointer<git_config_entry>>();
-  final nameC = variable.toChar();
+  final nameC = variable.toNativeUtf8().cast<Char>();
   final error = libgit2.git_config_get_entry(out, configPointer, nameC);
 
   final result = out.value;
@@ -168,7 +167,7 @@ void setBool({
   required String variable,
   required bool value,
 }) {
-  final nameC = variable.toChar();
+  final nameC = variable.toNativeUtf8().cast<Char>();
   final valueC = value ? 1 : 0;
   libgit2.git_config_set_bool(configPointer, nameC, valueC);
   calloc.free(nameC);
@@ -181,7 +180,7 @@ void setInt({
   required String variable,
   required int value,
 }) {
-  final nameC = variable.toChar();
+  final nameC = variable.toNativeUtf8().cast<Char>();
   libgit2.git_config_set_int64(configPointer, nameC, value);
   calloc.free(nameC);
 }
@@ -193,8 +192,8 @@ void setString({
   required String variable,
   required String value,
 }) {
-  final nameC = variable.toChar();
-  final valueC = value.toChar();
+  final nameC = variable.toNativeUtf8().cast<Char>();
+  final valueC = value.toNativeUtf8().cast<Char>();
   libgit2.git_config_set_string(configPointer, nameC, valueC);
   calloc.free(nameC);
   calloc.free(valueC);
@@ -221,7 +220,7 @@ void delete({
   required Pointer<git_config> configPointer,
   required String variable,
 }) {
-  final nameC = variable.toChar();
+  final nameC = variable.toNativeUtf8().cast<Char>();
   final error = libgit2.git_config_delete_entry(configPointer, nameC);
 
   calloc.free(nameC);
@@ -244,8 +243,8 @@ List<String> multivarValues({
   required String variable,
   String? regexp,
 }) {
-  final nameC = variable.toChar();
-  final regexpC = regexp?.toChar() ?? nullptr;
+  final nameC = variable.toNativeUtf8().cast<Char>();
+  final regexpC = regexp?.toNativeUtf8().cast<Char>() ?? nullptr;
   final iterator = calloc<Pointer<git_config_iterator>>();
   final entry = calloc<Pointer<git_config_entry>>();
 
@@ -262,7 +261,7 @@ List<String> multivarValues({
   while (error == 0) {
     error = libgit2.git_config_next(entry, iterator.value);
     if (error != -31) {
-      entries.add(entry.value.ref.value.toDartString());
+      entries.add(entry.value.ref.value.cast<Utf8>().toDartString());
     } else {
       break;
     }
@@ -287,9 +286,9 @@ void setMultivar({
   required String regexp,
   required String value,
 }) {
-  final nameC = variable.toChar();
-  final regexpC = regexp.toChar();
-  final valueC = value.toChar();
+  final nameC = variable.toNativeUtf8().cast<Char>();
+  final regexpC = regexp.toNativeUtf8().cast<Char>();
+  final valueC = value.toNativeUtf8().cast<Char>();
 
   libgit2.git_config_set_multivar(configPointer, nameC, regexpC, valueC);
 
@@ -307,8 +306,8 @@ void deleteMultivar({
   required String variable,
   required String regexp,
 }) {
-  final nameC = variable.toChar();
-  final regexpC = regexp.toChar();
+  final nameC = variable.toNativeUtf8().cast<Char>();
+  final regexpC = regexp.toNativeUtf8().cast<Char>();
 
   libgit2.git_config_delete_multivar(configPointer, nameC, regexpC);
 
diff --git a/lib/src/bindings/credentials.dart b/lib/src/bindings/credentials.dart
index 696e2ec..8b75c11 100644
--- a/lib/src/bindings/credentials.dart
+++ b/lib/src/bindings/credentials.dart
@@ -2,7 +2,6 @@ import 'dart:ffi';
 
 import 'package:ffi/ffi.dart';
 import 'package:libgit2dart/src/bindings/libgit2_bindings.dart';
-import 'package:libgit2dart/src/extensions.dart';
 import 'package:libgit2dart/src/util.dart';
 
 /// Create a new plain-text username and password credential object.
@@ -11,8 +10,8 @@ Pointer<git_credential> userPass({
   required String password,
 }) {
   final out = calloc<Pointer<git_credential>>();
-  final usernameC = username.toChar();
-  final passwordC = password.toChar();
+  final usernameC = username.toNativeUtf8().cast<Char>();
+  final passwordC = password.toNativeUtf8().cast<Char>();
 
   libgit2.git_credential_userpass_plaintext_new(out, usernameC, passwordC);
 
@@ -33,10 +32,10 @@ Pointer<git_credential> sshKey({
   required String passPhrase,
 }) {
   final out = calloc<Pointer<git_credential>>();
-  final usernameC = username.toChar();
-  final publicKeyC = publicKey.toChar();
-  final privateKeyC = privateKey.toChar();
-  final passPhraseC = passPhrase.toChar();
+  final usernameC = username.toNativeUtf8().cast<Char>();
+  final publicKeyC = publicKey.toNativeUtf8().cast<Char>();
+  final privateKeyC = privateKey.toNativeUtf8().cast<Char>();
+  final passPhraseC = passPhrase.toNativeUtf8().cast<Char>();
 
   libgit2.git_credential_ssh_key_new(
     out,
@@ -60,7 +59,7 @@ Pointer<git_credential> sshKey({
 /// Create a new ssh key credential object used for querying an ssh-agent.
 Pointer<git_credential> sshKeyFromAgent(String username) {
   final out = calloc<Pointer<git_credential>>();
-  final usernameC = username.toChar();
+  final usernameC = username.toNativeUtf8().cast<Char>();
 
   libgit2.git_credential_ssh_key_from_agent(out, usernameC);
 
@@ -80,10 +79,10 @@ Pointer<git_credential> sshKeyFromMemory({
   required String passPhrase,
 }) {
   final out = calloc<Pointer<git_credential>>();
-  final usernameC = username.toChar();
-  final publicKeyC = publicKey.toChar();
-  final privateKeyC = privateKey.toChar();
-  final passPhraseC = passPhrase.toChar();
+  final usernameC = username.toNativeUtf8().cast<Char>();
+  final publicKeyC = publicKey.toNativeUtf8().cast<Char>();
+  final privateKeyC = privateKey.toNativeUtf8().cast<Char>();
+  final passPhraseC = passPhrase.toNativeUtf8().cast<Char>();
 
   libgit2.git_credential_ssh_key_memory_new(
     out,
diff --git a/lib/src/bindings/describe.dart b/lib/src/bindings/describe.dart
index 4529f59..1fae8b5 100644
--- a/lib/src/bindings/describe.dart
+++ b/lib/src/bindings/describe.dart
@@ -3,7 +3,6 @@ import 'dart:ffi';
 import 'package:ffi/ffi.dart';
 import 'package:libgit2dart/src/bindings/libgit2_bindings.dart';
 import 'package:libgit2dart/src/error.dart';
-import 'package:libgit2dart/src/extensions.dart';
 import 'package:libgit2dart/src/util.dart';
 
 /// Describe a commit. The returned describe result must be freed with [free].
@@ -101,12 +100,12 @@ String format({
     opts.ref.always_use_long_format = alwaysUseLongFormat ? 1 : 0;
   }
   if (dirtySuffix != null) {
-    opts.ref.dirty_suffix = dirtySuffix.toChar();
+    opts.ref.dirty_suffix = dirtySuffix.toNativeUtf8().cast<Char>();
   }
 
   libgit2.git_describe_format(out, describeResultPointer, opts);
 
-  final result = out.ref.ptr.toDartString(length: out.ref.size);
+  final result = out.ref.ptr.cast<Utf8>().toDartString(length: out.ref.size);
 
   libgit2.git_buf_dispose(out);
   calloc.free(out);
@@ -141,7 +140,7 @@ Pointer<git_describe_options> _initOpts({
     opts.ref.describe_strategy = describeStrategy;
   }
   if (pattern != null) {
-    opts.ref.pattern = pattern.toChar();
+    opts.ref.pattern = pattern.toNativeUtf8().cast<Char>();
   }
   if (onlyFollowFirstParent != null) {
     opts.ref.only_follow_first_parent = onlyFollowFirstParent ? 1 : 0;
diff --git a/lib/src/bindings/diff.dart b/lib/src/bindings/diff.dart
index 8e1d27c..4a49417 100644
--- a/lib/src/bindings/diff.dart
+++ b/lib/src/bindings/diff.dart
@@ -3,7 +3,6 @@ import 'dart:ffi';
 import 'package:ffi/ffi.dart';
 import 'package:libgit2dart/src/bindings/libgit2_bindings.dart';
 import 'package:libgit2dart/src/error.dart';
-import 'package:libgit2dart/src/extensions.dart';
 import 'package:libgit2dart/src/util.dart';
 
 /// Create a diff with the difference between two index objects. The returned
@@ -254,7 +253,7 @@ void merge({
 /// other types of patch files.
 Pointer<git_diff> parse(String content) {
   final out = calloc<Pointer<git_diff>>();
-  final contentC = content.toChar();
+  final contentC = content.toNativeUtf8().cast<Char>();
   libgit2.git_diff_from_buffer(out, contentC, content.length);
 
   final result = out.value;
@@ -384,7 +383,7 @@ String statsPrint({
   final out = calloc<git_buf>();
   final error = libgit2.git_diff_stats_to_buf(out, statsPointer, format, width);
 
-  final result = out.ref.ptr.toDartString(length: out.ref.size);
+  final result = out.ref.ptr.cast<Utf8>().toDartString(length: out.ref.size);
 
   libgit2.git_buf_dispose(out);
   calloc.free(out);
@@ -403,7 +402,7 @@ String addToBuf(Pointer<git_diff> diff) {
 
   final result = out.ref.ptr == nullptr
       ? ''
-      : out.ref.ptr.toDartString(length: out.ref.size);
+      : out.ref.ptr.cast<Utf8>().toDartString(length: out.ref.size);
 
   libgit2.git_buf_dispose(out);
   calloc.free(out);
diff --git a/lib/src/bindings/index.dart b/lib/src/bindings/index.dart
index c7e1d06..ada8dc5 100644
--- a/lib/src/bindings/index.dart
+++ b/lib/src/bindings/index.dart
@@ -3,7 +3,6 @@ import 'dart:ffi';
 import 'package:ffi/ffi.dart';
 import 'package:libgit2dart/src/bindings/libgit2_bindings.dart';
 import 'package:libgit2dart/src/error.dart';
-import 'package:libgit2dart/src/extensions.dart';
 import 'package:libgit2dart/src/util.dart';
 
 /// Create an in-memory index object.
@@ -46,7 +45,7 @@ void setCapabilities({
 
 /// Get the full path to the index file on disk.
 String path(Pointer<git_index> index) {
-  return libgit2.git_index_path(index).toDartString();
+  return libgit2.git_index_path(index).cast<Utf8>().toDartString();
 }
 
 /// Update the contents of an existing index object in memory by reading from
@@ -126,7 +125,7 @@ Pointer<git_oid> writeTreeTo({
 /// Find the first position of any entries which point to given path in the Git
 /// index.
 bool find({required Pointer<git_index> indexPointer, required String path}) {
-  final pathC = path.toChar();
+  final pathC = path.toNativeUtf8().cast<Char>();
   final result = libgit2.git_index_find(nullptr, indexPointer, pathC);
 
   calloc.free(pathC);
@@ -165,7 +164,7 @@ Pointer<git_index_entry> getByPath({
   required String path,
   required int stage,
 }) {
-  final pathC = path.toChar();
+  final pathC = path.toNativeUtf8().cast<Char>();
   final result = libgit2.git_index_get_bypath(indexPointer, pathC, stage);
 
   calloc.free(pathC);
@@ -232,7 +231,7 @@ void addByPath({
   required Pointer<git_index> indexPointer,
   required String path,
 }) {
-  final pathC = path.toChar();
+  final pathC = path.toNativeUtf8().cast<Char>();
   final error = libgit2.git_index_add_bypath(indexPointer, pathC);
 
   calloc.free(pathC);
@@ -264,7 +263,7 @@ void addFromBuffer({
   required Pointer<git_index_entry> entryPointer,
   required String buffer,
 }) {
-  final bufferC = buffer.toChar();
+  final bufferC = buffer.toNativeUtf8().cast<Int8>();
   final error = libgit2.git_index_add_from_buffer(
     indexPointer,
     entryPointer,
@@ -294,7 +293,8 @@ void addAll({
   required List<String> pathspec,
 }) {
   final pathspecC = calloc<git_strarray>();
-  final pathPointers = pathspec.map((e) => e.toChar()).toList();
+  final pathPointers =
+      pathspec.map((e) => e.toNativeUtf8().cast<Char>()).toList();
   final strArray = calloc<Pointer<Char>>(pathspec.length);
 
   for (var i = 0; i < pathspec.length; i++) {
@@ -338,7 +338,8 @@ void updateAll({
   required List<String> pathspec,
 }) {
   final pathspecC = calloc<git_strarray>();
-  final pathPointers = pathspec.map((e) => e.toChar()).toList();
+  final pathPointers =
+      pathspec.map((e) => e.toNativeUtf8().cast<Char>()).toList();
   final strArray = calloc<Pointer<Char>>(pathspec.length);
 
   for (var i = 0; i < pathspec.length; i++) {
@@ -378,7 +379,7 @@ void remove({
   required String path,
   required int stage,
 }) {
-  final pathC = path.toChar();
+  final pathC = path.toNativeUtf8().cast<Char>();
   final error = libgit2.git_index_remove(indexPointer, pathC, stage);
 
   calloc.free(pathC);
@@ -394,7 +395,7 @@ void removeDirectory({
   required String dir,
   required int stage,
 }) {
-  final dirC = dir.toChar();
+  final dirC = dir.toNativeUtf8().cast<Char>();
   libgit2.git_index_remove_directory(indexPointer, dirC, stage);
   calloc.free(dirC);
 }
@@ -405,7 +406,8 @@ void removeAll({
   required List<String> pathspec,
 }) {
   final pathspecC = calloc<git_strarray>();
-  final pathPointers = pathspec.map((e) => e.toChar()).toList();
+  final pathPointers =
+      pathspec.map((e) => e.toNativeUtf8().cast<Char>()).toList();
   final strArray = calloc<Pointer<Char>>(pathspec.length);
 
   for (var i = 0; i < pathspec.length; i++) {
@@ -509,7 +511,7 @@ void conflictRemove({
   required Pointer<git_index> indexPointer,
   required String path,
 }) {
-  final pathC = path.toChar();
+  final pathC = path.toNativeUtf8().cast<Char>();
   final error = libgit2.git_index_conflict_remove(indexPointer, pathC);
 
   calloc.free(pathC);
diff --git a/lib/src/bindings/mailmap.dart b/lib/src/bindings/mailmap.dart
index 142acfd..fd4d52d 100644
--- a/lib/src/bindings/mailmap.dart
+++ b/lib/src/bindings/mailmap.dart
@@ -3,7 +3,6 @@ import 'dart:ffi';
 import 'package:ffi/ffi.dart';
 import 'package:libgit2dart/src/bindings/libgit2_bindings.dart';
 import 'package:libgit2dart/src/error.dart';
-import 'package:libgit2dart/src/extensions.dart';
 import 'package:libgit2dart/src/util.dart';
 
 /// Allocate a new mailmap object. The returned mailmap must be freed with
@@ -26,7 +25,7 @@ Pointer<git_mailmap> init() {
 /// returned mailmap must be freed with [free].
 Pointer<git_mailmap> fromBuffer(String buffer) {
   final out = calloc<Pointer<git_mailmap>>();
-  final bufferC = buffer.toChar();
+  final bufferC = buffer.toNativeUtf8().cast<Char>();
 
   libgit2.git_mailmap_from_buffer(out, bufferC, buffer.length);
 
@@ -73,8 +72,8 @@ List<String> resolve({
 }) {
   final outRealName = calloc<Pointer<Char>>();
   final outRealEmail = calloc<Pointer<Char>>();
-  final nameC = name.toChar();
-  final emailC = email.toChar();
+  final nameC = name.toNativeUtf8().cast<Char>();
+  final emailC = email.toNativeUtf8().cast<Char>();
   libgit2.git_mailmap_resolve(
     outRealName,
     outRealEmail,
@@ -83,8 +82,8 @@ List<String> resolve({
     emailC,
   );
 
-  final realName = outRealName.value.toDartString();
-  final realEmail = outRealEmail.value.toDartString();
+  final realName = outRealName.value.cast<Utf8>().toDartString();
+  final realEmail = outRealEmail.value.cast<Utf8>().toDartString();
   calloc.free(outRealName);
   calloc.free(outRealEmail);
   calloc.free(nameC);
@@ -120,10 +119,10 @@ void addEntry({
   String? replaceName,
   required String replaceEmail,
 }) {
-  final realNameC = realName?.toChar() ?? nullptr;
-  final realEmailC = realEmail?.toChar() ?? nullptr;
-  final replaceNameC = replaceName?.toChar() ?? nullptr;
-  final replaceEmailC = replaceEmail.toChar();
+  final realNameC = realName?.toNativeUtf8().cast<Char>() ?? nullptr;
+  final realEmailC = realEmail?.toNativeUtf8().cast<Char>() ?? nullptr;
+  final replaceNameC = replaceName?.toNativeUtf8().cast<Char>() ?? nullptr;
+  final replaceEmailC = replaceEmail.toNativeUtf8().cast<Char>();
 
   libgit2.git_mailmap_add_entry(
     mailmapPointer,
diff --git a/lib/src/bindings/merge.dart b/lib/src/bindings/merge.dart
index 88229bf..ecceee3 100644
--- a/lib/src/bindings/merge.dart
+++ b/lib/src/bindings/merge.dart
@@ -3,7 +3,6 @@ import 'dart:ffi';
 import 'package:ffi/ffi.dart';
 import 'package:libgit2dart/src/bindings/libgit2_bindings.dart';
 import 'package:libgit2dart/src/error.dart';
-import 'package:libgit2dart/src/extensions.dart';
 import 'package:libgit2dart/src/util.dart';
 
 /// Find a merge base between two commits.
@@ -184,11 +183,11 @@ String mergeFile({
   libgit2.git_merge_file_input_init(ancestorC, GIT_MERGE_FILE_INPUT_VERSION);
   libgit2.git_merge_file_input_init(oursC, GIT_MERGE_FILE_INPUT_VERSION);
   libgit2.git_merge_file_input_init(theirsC, GIT_MERGE_FILE_INPUT_VERSION);
-  ancestorC.ref.ptr = ancestor.toChar();
+  ancestorC.ref.ptr = ancestor.toNativeUtf8().cast<Char>();
   ancestorC.ref.size = ancestor.length;
-  oursC.ref.ptr = ours.toChar();
+  oursC.ref.ptr = ours.toNativeUtf8().cast<Char>();
   oursC.ref.size = ours.length;
-  theirsC.ref.ptr = theirs.toChar();
+  theirsC.ref.ptr = theirs.toNativeUtf8().cast<Char>();
   theirsC.ref.size = theirs.length;
 
   final opts = calloc<git_merge_file_options>();
@@ -196,13 +195,13 @@ String mergeFile({
   opts.ref.favor = favor;
   opts.ref.flags = flags;
   if (ancestorLabel.isNotEmpty) {
-    opts.ref.ancestor_label = ancestorLabel.toChar();
+    opts.ref.ancestor_label = ancestorLabel.toNativeUtf8().cast<Char>();
   }
   if (oursLabel.isNotEmpty) {
-    opts.ref.our_label = oursLabel.toChar();
+    opts.ref.our_label = oursLabel.toNativeUtf8().cast<Char>();
   }
   if (theirsLabel.isNotEmpty) {
-    opts.ref.their_label = theirsLabel.toChar();
+    opts.ref.their_label = theirsLabel.toNativeUtf8().cast<Char>();
   }
 
   libgit2.git_merge_file(out, ancestorC, oursC, theirsC, opts);
@@ -212,7 +211,7 @@ String mergeFile({
   calloc.free(theirsC);
   calloc.free(opts);
 
-  final result = out.ref.ptr.toDartString(length: out.ref.len);
+  final result = out.ref.ptr.cast<Utf8>().toDartString(length: out.ref.len);
   calloc.free(out);
 
   return result;
@@ -241,7 +240,7 @@ String mergeFileFromIndex({
 
   late final String result;
   if (out.ref.ptr != nullptr) {
-    result = out.ref.ptr.toDartString(length: out.ref.len);
+    result = out.ref.ptr.cast<Utf8>().toDartString(length: out.ref.len);
   }
 
   calloc.free(out);
diff --git a/lib/src/bindings/note.dart b/lib/src/bindings/note.dart
index bf7f58a..d87e3c2 100644
--- a/lib/src/bindings/note.dart
+++ b/lib/src/bindings/note.dart
@@ -3,24 +3,16 @@ import 'dart:ffi';
 import 'package:ffi/ffi.dart';
 import 'package:libgit2dart/src/bindings/libgit2_bindings.dart';
 import 'package:libgit2dart/src/error.dart';
-import 'package:libgit2dart/src/extensions.dart';
 import 'package:libgit2dart/src/util.dart';
 
 /// Returns list of notes for repository. The returned notes must be freed with
 /// [free].
 ///
 /// Throws a [LibGit2Error] if error occured.
-List<Map<String, Pointer>> list({
-  required Pointer<git_repository> repoPointer,
-  required String notesRef,
-}) {
-  final notesRefC = notesRef.toChar();
+List<Map<String, Pointer>> list(Pointer<git_repository> repo) {
+  final notesRef = 'refs/notes/commits'.toNativeUtf8().cast<Char>();
   final iterator = calloc<Pointer<git_iterator>>();
-  final iteratorError = libgit2.git_note_iterator_new(
-    iterator,
-    repoPointer,
-    notesRefC,
-  );
+  final iteratorError = libgit2.git_note_iterator_new(iterator, repo, notesRef);
 
   if (iteratorError < 0) {
     calloc.free(iterator);
@@ -36,7 +28,7 @@ List<Map<String, Pointer>> list({
     nextError = libgit2.git_note_next(noteOid, annotatedOid, iterator.value);
     if (nextError >= 0) {
       final out = calloc<Pointer<git_note>>();
-      libgit2.git_note_read(out, repoPointer, notesRefC, annotatedOid);
+      libgit2.git_note_read(out, repo, notesRef, annotatedOid);
 
       final note = out.value;
 
@@ -49,7 +41,7 @@ List<Map<String, Pointer>> list({
     calloc.free(noteOid);
   }
 
-  calloc.free(notesRefC);
+  calloc.free(notesRef);
   libgit2.git_note_iterator_free(iterator.value);
   calloc.free(iterator);
 
@@ -62,10 +54,10 @@ List<Map<String, Pointer>> list({
 Pointer<git_note> lookup({
   required Pointer<git_repository> repoPointer,
   required Pointer<git_oid> oidPointer,
-  required String notesRef,
+  String notesRef = 'refs/notes/commits',
 }) {
   final out = calloc<Pointer<git_note>>();
-  final notesRefC = notesRef.toChar();
+  final notesRefC = notesRef.toNativeUtf8().cast<Char>();
   final error = libgit2.git_note_read(out, repoPointer, notesRefC, oidPointer);
 
   final result = out.value;
@@ -93,8 +85,8 @@ Pointer<git_oid> create({
   bool force = false,
 }) {
   final out = calloc<git_oid>();
-  final notesRefC = notesRef.toChar();
-  final noteC = note.toChar();
+  final notesRefC = notesRef.toNativeUtf8().cast<Char>();
+  final noteC = note.toNativeUtf8().cast<Char>();
   final forceC = force ? 1 : 0;
   final error = libgit2.git_note_create(
     out,
@@ -128,7 +120,7 @@ void delete({
   required Pointer<git_signature> committerPointer,
   required Pointer<git_oid> oidPointer,
 }) {
-  final notesRefC = notesRef.toChar();
+  final notesRefC = notesRef.toNativeUtf8().cast<Char>();
 
   final error = libgit2.git_note_remove(
     repoPointer,
@@ -150,7 +142,7 @@ Pointer<git_oid> id(Pointer<git_note> note) => libgit2.git_note_id(note);
 
 /// Get the note message.
 String message(Pointer<git_note> note) {
-  return libgit2.git_note_message(note).toDartString();
+  return libgit2.git_note_message(note).cast<Utf8>().toDartString();
 }
 
 /// Free memory allocated for note object.
diff --git a/lib/src/bindings/odb.dart b/lib/src/bindings/odb.dart
index 33aa62f..7ef461e 100644
--- a/lib/src/bindings/odb.dart
+++ b/lib/src/bindings/odb.dart
@@ -4,7 +4,6 @@ import 'package:ffi/ffi.dart';
 import 'package:libgit2dart/src/bindings/libgit2_bindings.dart';
 import 'package:libgit2dart/src/bindings/oid.dart' as oid_bindings;
 import 'package:libgit2dart/src/error.dart';
-import 'package:libgit2dart/src/extensions.dart';
 import 'package:libgit2dart/src/oid.dart';
 import 'package:libgit2dart/src/util.dart';
 
@@ -37,7 +36,7 @@ void addDiskAlternate({
   required Pointer<git_odb> odbPointer,
   required String path,
 }) {
-  final pathC = path.toChar();
+  final pathC = path.toNativeUtf8().cast<Char>();
   libgit2.git_odb_add_disk_alternate(odbPointer, pathC);
   calloc.free(pathC);
 }
@@ -185,7 +184,7 @@ Pointer<git_oid> write({
     throw LibGit2Error(libgit2.git_error_last());
   }
 
-  final bufferC = data.toChar();
+  final bufferC = data.toNativeUtf8().cast<Char>();
   libgit2.git_odb_stream_write(stream.value, bufferC, data.length);
 
   final out = calloc<git_oid>();
diff --git a/lib/src/bindings/oid.dart b/lib/src/bindings/oid.dart
index 2b061e5..2de419c 100644
--- a/lib/src/bindings/oid.dart
+++ b/lib/src/bindings/oid.dart
@@ -2,13 +2,12 @@ import 'dart:ffi';
 
 import 'package:ffi/ffi.dart';
 import 'package:libgit2dart/src/bindings/libgit2_bindings.dart';
-import 'package:libgit2dart/src/extensions.dart';
 import 'package:libgit2dart/src/util.dart';
 
 /// Parse N characters of a hex formatted object id into a git_oid.
 Pointer<git_oid> fromStrN(String hex) {
   final out = calloc<git_oid>();
-  final hexC = hex.toChar();
+  final hexC = hex.toNativeUtf8().cast<Char>();
   libgit2.git_oid_fromstrn(out, hexC, hex.length);
 
   calloc.free(hexC);
@@ -19,7 +18,7 @@ Pointer<git_oid> fromStrN(String hex) {
 /// Parse a hex formatted object id into a git_oid.
 Pointer<git_oid> fromSHA(String hex) {
   final out = calloc<git_oid>();
-  final hexC = hex.toChar();
+  final hexC = hex.toNativeUtf8().cast<Char>();
   libgit2.git_oid_fromstr(out, hexC);
 
   calloc.free(hexC);
@@ -48,7 +47,7 @@ String toSHA(Pointer<git_oid> id) {
   final out = calloc<Char>(40);
   libgit2.git_oid_fmt(out, id);
 
-  final result = out.toDartString(length: 40);
+  final result = out.cast<Utf8>().toDartString(length: 40);
   calloc.free(out);
   return result;
 }
diff --git a/lib/src/bindings/packbuilder.dart b/lib/src/bindings/packbuilder.dart
index 9d5aae1..026e2a9 100644
--- a/lib/src/bindings/packbuilder.dart
+++ b/lib/src/bindings/packbuilder.dart
@@ -3,7 +3,6 @@ import 'dart:ffi';
 import 'package:ffi/ffi.dart';
 import 'package:libgit2dart/src/bindings/libgit2_bindings.dart';
 import 'package:libgit2dart/src/error.dart';
-import 'package:libgit2dart/src/extensions.dart';
 import 'package:libgit2dart/src/util.dart';
 
 /// Initialize a new packbuilder. The returned packbuilder must be freed with
@@ -122,7 +121,7 @@ void write({
   required Pointer<git_packbuilder> packbuilderPointer,
   String? path,
 }) {
-  final pathC = path?.toChar() ?? nullptr;
+  final pathC = path?.toNativeUtf8().cast<Char>() ?? nullptr;
   final error = libgit2.git_packbuilder_write(
     packbuilderPointer,
     pathC,
@@ -154,7 +153,7 @@ int writtenCount(Pointer<git_packbuilder> pb) {
 /// correct after the packfile has been written.
 String name(Pointer<git_packbuilder> pb) {
   final result = libgit2.git_packbuilder_name(pb);
-  return result == nullptr ? '' : result.toDartString();
+  return result == nullptr ? '' : result.cast<Utf8>().toDartString();
 }
 
 /// Set number of threads to spawn.
diff --git a/lib/src/bindings/patch.dart b/lib/src/bindings/patch.dart
index 5815ed4..53e7020 100644
--- a/lib/src/bindings/patch.dart
+++ b/lib/src/bindings/patch.dart
@@ -3,7 +3,6 @@ import 'dart:ffi';
 import 'package:ffi/ffi.dart';
 import 'package:libgit2dart/src/bindings/libgit2_bindings.dart';
 import 'package:libgit2dart/src/error.dart';
-import 'package:libgit2dart/src/extensions.dart';
 import 'package:libgit2dart/src/util.dart';
 
 /// Directly generate a patch from the difference between two buffers. The
@@ -18,11 +17,11 @@ Pointer<git_patch> fromBuffers({
   required int interhunkLines,
 }) {
   final out = calloc<Pointer<git_patch>>();
-  final oldBufferC = oldBuffer?.toChar() ?? nullptr;
-  final oldAsPathC = oldAsPath?.toChar() ?? nullptr;
+  final oldBufferC = oldBuffer?.toNativeUtf8().cast<Char>() ?? nullptr;
+  final oldAsPathC = oldAsPath?.toNativeUtf8().cast<Char>() ?? nullptr;
   final oldLen = oldBuffer?.length ?? 0;
-  final newBufferC = newBuffer?.toChar() ?? nullptr;
-  final newAsPathC = oldAsPath?.toChar() ?? nullptr;
+  final newBufferC = newBuffer?.toNativeUtf8().cast<Char>() ?? nullptr;
+  final newAsPathC = oldAsPath?.toNativeUtf8().cast<Char>() ?? nullptr;
   final newLen = newBuffer?.length ?? 0;
   final opts = _diffOptionsInit(
     flags: flags,
@@ -66,8 +65,8 @@ Pointer<git_patch> fromBlobs({
   required int interhunkLines,
 }) {
   final out = calloc<Pointer<git_patch>>();
-  final oldAsPathC = oldAsPath?.toChar() ?? nullptr;
-  final newAsPathC = oldAsPath?.toChar() ?? nullptr;
+  final oldAsPathC = oldAsPath?.toNativeUtf8().cast<Char>() ?? nullptr;
+  final newAsPathC = oldAsPath?.toNativeUtf8().cast<Char>() ?? nullptr;
   final opts = _diffOptionsInit(
     flags: flags,
     contextLines: contextLines,
@@ -105,9 +104,9 @@ Pointer<git_patch> fromBlobAndBuffer({
   required int interhunkLines,
 }) {
   final out = calloc<Pointer<git_patch>>();
-  final oldAsPathC = oldAsPath?.toChar() ?? nullptr;
-  final bufferC = buffer?.toChar() ?? nullptr;
-  final bufferAsPathC = oldAsPath?.toChar() ?? nullptr;
+  final oldAsPathC = oldAsPath?.toNativeUtf8().cast<Char>() ?? nullptr;
+  final bufferC = buffer?.toNativeUtf8().cast<Char>() ?? nullptr;
+  final bufferAsPathC = oldAsPath?.toNativeUtf8().cast<Char>() ?? nullptr;
   final bufferLen = buffer?.length ?? 0;
   final opts = _diffOptionsInit(
     flags: flags,
@@ -176,8 +175,8 @@ Map<String, Object> hunk({
   required int hunkIndex,
 }) {
   final out = calloc<Pointer<git_diff_hunk>>();
-  final linesInHunk = calloc<Size>();
-  libgit2.git_patch_get_hunk(out, linesInHunk, patchPointer, hunkIndex);
+  final linesInHunk = calloc<Int64>();
+  libgit2.git_patch_get_hunk(out, linesInHunk.cast(), patchPointer, hunkIndex);
 
   final hunk = out.value;
   final linesN = linesInHunk.value;
@@ -236,7 +235,7 @@ String text(Pointer<git_patch> patch) {
   final out = calloc<git_buf>();
   final error = libgit2.git_patch_to_buf(out, patch);
 
-  final result = out.ref.ptr.toDartString(length: out.ref.size);
+  final result = out.ref.ptr.cast<Utf8>().toDartString(length: out.ref.size);
 
   libgit2.git_buf_dispose(out);
   calloc.free(out);
diff --git a/lib/src/bindings/rebase.dart b/lib/src/bindings/rebase.dart
index 71e8d09..3dabb35 100644
--- a/lib/src/bindings/rebase.dart
+++ b/lib/src/bindings/rebase.dart
@@ -3,7 +3,6 @@ import 'dart:ffi';
 import 'package:ffi/ffi.dart';
 import 'package:libgit2dart/src/bindings/libgit2_bindings.dart';
 import 'package:libgit2dart/src/error.dart';
-import 'package:libgit2dart/src/extensions.dart';
 import 'package:libgit2dart/src/util.dart';
 
 /// Initializes a rebase operation to rebase the changes in [branchPointer]
@@ -129,7 +128,7 @@ void commit({
   required String? message,
 }) {
   final out = calloc<git_oid>();
-  final messageC = message?.toChar() ?? nullptr;
+  final messageC = message?.toNativeUtf8().cast<Char>() ?? nullptr;
 
   final error = libgit2.git_rebase_commit(
     out,
@@ -164,7 +163,7 @@ Pointer<git_oid> origHeadOid(Pointer<git_rebase> rebase) =>
 /// Gets the original HEAD ref name for merge rebases.
 String origHeadName(Pointer<git_rebase> rebase) {
   final result = libgit2.git_rebase_orig_head_name(rebase);
-  return result == nullptr ? '' : result.toDartString();
+  return result == nullptr ? '' : result.cast<Utf8>().toDartString();
 }
 
 /// Gets the onto id for merge rebases.
@@ -173,7 +172,7 @@ Pointer<git_oid> ontoOid(Pointer<git_rebase> rebase) =>
 
 /// Gets the onto ref name for merge rebases.
 String ontoName(Pointer<git_rebase> rebase) {
-  return libgit2.git_rebase_onto_name(rebase).toDartString();
+  return libgit2.git_rebase_onto_name(rebase).cast<Utf8>().toDartString();
 }
 
 /// Free memory allocated for rebase object.
diff --git a/lib/src/bindings/reference.dart b/lib/src/bindings/reference.dart
index 81e190c..cff69b8 100644
--- a/lib/src/bindings/reference.dart
+++ b/lib/src/bindings/reference.dart
@@ -3,7 +3,6 @@ import 'dart:ffi';
 import 'package:ffi/ffi.dart';
 import 'package:libgit2dart/src/bindings/libgit2_bindings.dart';
 import 'package:libgit2dart/src/error.dart';
-import 'package:libgit2dart/src/extensions.dart';
 import 'package:libgit2dart/src/util.dart';
 
 /// Get the type of a reference.
@@ -56,7 +55,7 @@ Pointer<git_reference> lookup({
   required String name,
 }) {
   final out = calloc<Pointer<git_reference>>();
-  final nameC = name.toChar();
+  final nameC = name.toNativeUtf8().cast<Char>();
   final error = libgit2.git_reference_lookup(out, repoPointer, nameC);
 
   final result = out.value;
@@ -73,7 +72,7 @@ Pointer<git_reference> lookup({
 
 /// Get the full name of a reference.
 String name(Pointer<git_reference> ref) {
-  return libgit2.git_reference_name(ref).toDartString();
+  return libgit2.git_reference_name(ref).cast<Utf8>().toDartString();
 }
 
 /// Get the reference's short name.
@@ -81,7 +80,7 @@ String name(Pointer<git_reference> ref) {
 /// This will transform the reference name into a name "human-readable" version.
 /// If no shortname is appropriate, it will return the full name.
 String shorthand(Pointer<git_reference> ref) {
-  return libgit2.git_reference_shorthand(ref).toDartString();
+  return libgit2.git_reference_shorthand(ref).cast<Utf8>().toDartString();
 }
 
 /// Rename an existing reference. The returned reference must be freed with
@@ -105,9 +104,9 @@ Pointer<git_reference> rename({
   String? logMessage,
 }) {
   final out = calloc<Pointer<git_reference>>();
-  final newNameC = newName.toChar();
+  final newNameC = newName.toNativeUtf8().cast<Char>();
   final forceC = force == true ? 1 : 0;
-  final logMessageC = logMessage?.toChar() ?? nullptr;
+  final logMessageC = logMessage?.toNativeUtf8().cast<Char>() ?? nullptr;
   final error = libgit2.git_reference_rename(
     out,
     refPointer,
@@ -141,7 +140,9 @@ List<String> list(Pointer<git_repository> repo) {
     throw LibGit2Error(libgit2.git_error_last());
   } else {
     for (var i = 0; i < array.ref.count; i++) {
-      result.add(array.ref.strings.elementAt(i).value.toDartString());
+      result.add(
+        array.ref.strings.elementAt(i).value.cast<Utf8>().toDartString(),
+      );
     }
   }
 
@@ -155,7 +156,7 @@ bool hasLog({
   required Pointer<git_repository> repoPointer,
   required String name,
 }) {
-  final nameC = name.toChar();
+  final nameC = name.toNativeUtf8().cast<Char>();
   final result = libgit2.git_reference_has_log(repoPointer, nameC);
 
   calloc.free(nameC);
@@ -172,7 +173,7 @@ void ensureLog({
   required Pointer<git_repository> repoPointer,
   required String refName,
 }) {
-  final refNameC = refName.toChar();
+  final refNameC = refName.toNativeUtf8().cast<Char>();
   final error = libgit2.git_reference_ensure_log(repoPointer, refNameC);
 
   calloc.free(refNameC);
@@ -236,9 +237,9 @@ Pointer<git_reference> createDirect({
   String? logMessage,
 }) {
   final out = calloc<Pointer<git_reference>>();
-  final nameC = name.toChar();
+  final nameC = name.toNativeUtf8().cast<Char>();
   final forceC = force == true ? 1 : 0;
-  final logMessageC = logMessage?.toChar() ?? nullptr;
+  final logMessageC = logMessage?.toNativeUtf8().cast<Char>() ?? nullptr;
   final error = libgit2.git_reference_create(
     out,
     repoPointer,
@@ -294,10 +295,10 @@ Pointer<git_reference> createSymbolic({
   String? logMessage,
 }) {
   final out = calloc<Pointer<git_reference>>();
-  final nameC = name.toChar();
-  final targetC = target.toChar();
+  final nameC = name.toNativeUtf8().cast<Char>();
+  final targetC = target.toNativeUtf8().cast<Char>();
   final forceC = force == true ? 1 : 0;
-  final logMessageC = logMessage?.toChar() ?? nullptr;
+  final logMessageC = logMessage?.toNativeUtf8().cast<Char>() ?? nullptr;
   final error = libgit2.git_reference_symbolic_create(
     out,
     repoPointer,
@@ -347,7 +348,7 @@ Pointer<git_reference> setTarget({
   String? logMessage,
 }) {
   final out = calloc<Pointer<git_reference>>();
-  final logMessageC = logMessage?.toChar() ?? nullptr;
+  final logMessageC = logMessage?.toNativeUtf8().cast<Char>() ?? nullptr;
   final error = libgit2.git_reference_set_target(
     out,
     refPointer,
@@ -387,8 +388,8 @@ Pointer<git_reference> setTargetSymbolic({
   String? logMessage,
 }) {
   final out = calloc<Pointer<git_reference>>();
-  final targetC = target.toChar();
-  final logMessageC = logMessage?.toChar() ?? nullptr;
+  final targetC = target.toNativeUtf8().cast<Char>();
+  final logMessageC = logMessage?.toNativeUtf8().cast<Char>() ?? nullptr;
   final error = libgit2.git_reference_symbolic_set_target(
     out,
     refPointer,
diff --git a/lib/src/bindings/reflog.dart b/lib/src/bindings/reflog.dart
index ff982f2..1fbd1da 100644
--- a/lib/src/bindings/reflog.dart
+++ b/lib/src/bindings/reflog.dart
@@ -3,7 +3,6 @@ import 'dart:ffi';
 import 'package:ffi/ffi.dart';
 import 'package:libgit2dart/src/bindings/libgit2_bindings.dart';
 import 'package:libgit2dart/src/error.dart';
-import 'package:libgit2dart/src/extensions.dart';
 import 'package:libgit2dart/src/util.dart';
 
 /// Read the reflog for the given reference. The returned reflog must be
@@ -16,7 +15,7 @@ Pointer<git_reflog> read({
   required String name,
 }) {
   final out = calloc<Pointer<git_reflog>>();
-  final nameC = name.toChar();
+  final nameC = name.toNativeUtf8().cast<Char>();
   libgit2.git_reflog_read(out, repoPointer, nameC);
 
   final result = out.value;
@@ -44,7 +43,7 @@ void delete({
   required Pointer<git_repository> repoPointer,
   required String name,
 }) {
-  final nameC = name.toChar();
+  final nameC = name.toNativeUtf8().cast<Char>();
   libgit2.git_reflog_delete(repoPointer, nameC);
   calloc.free(nameC);
 }
@@ -61,8 +60,8 @@ void rename({
   required String oldName,
   required String newName,
 }) {
-  final oldNameC = oldName.toChar();
-  final newNameC = newName.toChar();
+  final oldNameC = oldName.toNativeUtf8().cast<Char>();
+  final newNameC = newName.toNativeUtf8().cast<Char>();
   final error = libgit2.git_reflog_rename(repoPointer, oldNameC, newNameC);
 
   calloc.free(oldNameC);
@@ -82,7 +81,8 @@ void add({
   required Pointer<git_signature> committerPointer,
   required String message,
 }) {
-  final messageC = message.isEmpty ? nullptr : message.toChar();
+  final messageC =
+      message.isEmpty ? nullptr : message.toNativeUtf8().cast<Char>();
 
   final error = libgit2.git_reflog_append(
     reflogPointer,
@@ -130,7 +130,7 @@ Pointer<git_reflog_entry> getByIndex({
 /// Get the log message.
 String entryMessage(Pointer<git_reflog_entry> entry) {
   final result = libgit2.git_reflog_entry_message(entry);
-  return result == nullptr ? '' : result.toDartString();
+  return result == nullptr ? '' : result.cast<Utf8>().toDartString();
 }
 
 /// Get the committer of this entry. The returned signature must be freed.
diff --git a/lib/src/bindings/refspec.dart b/lib/src/bindings/refspec.dart
index c42ffa2..6d0c1a4 100644
--- a/lib/src/bindings/refspec.dart
+++ b/lib/src/bindings/refspec.dart
@@ -3,17 +3,16 @@ import 'dart:ffi';
 import 'package:ffi/ffi.dart';
 import 'package:libgit2dart/src/bindings/libgit2_bindings.dart';
 import 'package:libgit2dart/src/error.dart';
-import 'package:libgit2dart/src/extensions.dart';
 import 'package:libgit2dart/src/util.dart';
 
 /// Get the source specifier.
 String source(Pointer<git_refspec> refspec) {
-  return libgit2.git_refspec_src(refspec).toDartString();
+  return libgit2.git_refspec_src(refspec).cast<Utf8>().toDartString();
 }
 
 /// Get the destination specifier.
 String destination(Pointer<git_refspec> refspec) {
-  return libgit2.git_refspec_dst(refspec).toDartString();
+  return libgit2.git_refspec_dst(refspec).cast<Utf8>().toDartString();
 }
 
 /// Get the force update setting.
@@ -23,7 +22,7 @@ bool force(Pointer<git_refspec> refspec) {
 
 /// Get the refspec's string.
 String string(Pointer<git_refspec> refspec) {
-  return libgit2.git_refspec_string(refspec).toDartString();
+  return libgit2.git_refspec_string(refspec).cast<Utf8>().toDartString();
 }
 
 /// Get the refspec's direction.
@@ -35,7 +34,7 @@ bool matchesSource({
   required Pointer<git_refspec> refspecPointer,
   required String refname,
 }) {
-  final refnameC = refname.toChar();
+  final refnameC = refname.toNativeUtf8().cast<Char>();
   final result = libgit2.git_refspec_src_matches(refspecPointer, refnameC);
 
   calloc.free(refnameC);
@@ -48,7 +47,7 @@ bool matchesDestination({
   required Pointer<git_refspec> refspecPointer,
   required String refname,
 }) {
-  final refnameC = refname.toChar();
+  final refnameC = refname.toNativeUtf8().cast<Char>();
   final result = libgit2.git_refspec_dst_matches(refspecPointer, refnameC);
 
   calloc.free(refnameC);
@@ -64,10 +63,10 @@ String transform({
   required String name,
 }) {
   final out = calloc<git_buf>();
-  final nameC = name.toChar();
+  final nameC = name.toNativeUtf8().cast<Char>();
   final error = libgit2.git_refspec_transform(out, refspecPointer, nameC);
 
-  final result = out.ref.ptr.toDartString(length: out.ref.size);
+  final result = out.ref.ptr.cast<Utf8>().toDartString(length: out.ref.size);
 
   libgit2.git_buf_dispose(out);
   calloc.free(out);
@@ -89,10 +88,10 @@ String rTransform({
   required String name,
 }) {
   final out = calloc<git_buf>();
-  final nameC = name.toChar();
+  final nameC = name.toNativeUtf8().cast<Char>();
   final error = libgit2.git_refspec_rtransform(out, refspecPointer, nameC);
 
-  final result = out.ref.ptr.toDartString(length: out.ref.size);
+  final result = out.ref.ptr.cast<Utf8>().toDartString(length: out.ref.size);
 
   libgit2.git_buf_dispose(out);
   calloc.free(out);
diff --git a/lib/src/bindings/remote.dart b/lib/src/bindings/remote.dart
index 6c68426..3305c7e 100644
--- a/lib/src/bindings/remote.dart
+++ b/lib/src/bindings/remote.dart
@@ -5,7 +5,6 @@ import 'package:libgit2dart/src/bindings/libgit2_bindings.dart';
 import 'package:libgit2dart/src/bindings/remote_callbacks.dart';
 import 'package:libgit2dart/src/callbacks.dart';
 import 'package:libgit2dart/src/error.dart';
-import 'package:libgit2dart/src/extensions.dart';
 import 'package:libgit2dart/src/oid.dart';
 import 'package:libgit2dart/src/util.dart';
 
@@ -15,7 +14,8 @@ List<String> list(Pointer<git_repository> repo) {
   libgit2.git_remote_list(out, repo);
 
   final result = <String>[
-    for (var i = 0; i < out.ref.count; i++) out.ref.strings[i].toDartString()
+    for (var i = 0; i < out.ref.count; i++)
+      out.ref.strings[i].cast<Utf8>().toDartString()
   ];
 
   calloc.free(out);
@@ -34,7 +34,7 @@ Pointer<git_remote> lookup({
   required String name,
 }) {
   final out = calloc<Pointer<git_remote>>();
-  final nameC = name.toChar();
+  final nameC = name.toNativeUtf8().cast<Char>();
   final error = libgit2.git_remote_lookup(out, repoPointer, nameC);
 
   final result = out.value;
@@ -59,8 +59,8 @@ Pointer<git_remote> create({
   required String url,
 }) {
   final out = calloc<Pointer<git_remote>>();
-  final nameC = name.toChar();
-  final urlC = url.toChar();
+  final nameC = name.toNativeUtf8().cast<Char>();
+  final urlC = url.toNativeUtf8().cast<Char>();
   final error = libgit2.git_remote_create(out, repoPointer, nameC, urlC);
 
   final result = out.value;
@@ -87,9 +87,9 @@ Pointer<git_remote> createWithFetchSpec({
   required String fetch,
 }) {
   final out = calloc<Pointer<git_remote>>();
-  final nameC = name.toChar();
-  final urlC = url.toChar();
-  final fetchC = fetch.toChar();
+  final nameC = name.toNativeUtf8().cast<Char>();
+  final urlC = url.toNativeUtf8().cast<Char>();
+  final fetchC = fetch.toNativeUtf8().cast<Char>();
   final error = libgit2.git_remote_create_with_fetchspec(
     out,
     repoPointer,
@@ -122,7 +122,7 @@ void delete({
   required Pointer<git_repository> repoPointer,
   required String name,
 }) {
-  final nameC = name.toChar();
+  final nameC = name.toNativeUtf8().cast<Char>();
   final error = libgit2.git_remote_delete(repoPointer, nameC);
 
   calloc.free(nameC);
@@ -151,8 +151,8 @@ List<String> rename({
   required String newName,
 }) {
   final out = calloc<git_strarray>();
-  final nameC = name.toChar();
-  final newNameC = newName.toChar();
+  final nameC = name.toNativeUtf8().cast<Char>();
+  final newNameC = newName.toNativeUtf8().cast<Char>();
   final error = libgit2.git_remote_rename(out, repoPointer, nameC, newNameC);
 
   calloc.free(nameC);
@@ -163,7 +163,8 @@ List<String> rename({
     throw LibGit2Error(libgit2.git_error_last());
   } else {
     final result = <String>[
-      for (var i = 0; i < out.ref.count; i++) out.ref.strings[i].toDartString()
+      for (var i = 0; i < out.ref.count; i++)
+        out.ref.strings[i].cast<Utf8>().toDartString()
     ];
 
     calloc.free(out);
@@ -183,8 +184,8 @@ void setUrl({
   required String remote,
   required String url,
 }) {
-  final remoteC = remote.toChar();
-  final urlC = url.toChar();
+  final remoteC = remote.toNativeUtf8().cast<Char>();
+  final urlC = url.toNativeUtf8().cast<Char>();
   final error = libgit2.git_remote_set_url(repoPointer, remoteC, urlC);
 
   calloc.free(remoteC);
@@ -206,8 +207,8 @@ void setPushUrl({
   required String remote,
   required String url,
 }) {
-  final remoteC = remote.toChar();
-  final urlC = url.toChar();
+  final remoteC = remote.toNativeUtf8().cast<Char>();
+  final urlC = url.toNativeUtf8().cast<Char>();
   final error = libgit2.git_remote_set_pushurl(repoPointer, remoteC, urlC);
 
   calloc.free(remoteC);
@@ -221,12 +222,12 @@ void setPushUrl({
 /// Get the remote's name.
 String name(Pointer<git_remote> remote) {
   final result = libgit2.git_remote_name(remote);
-  return result == nullptr ? '' : result.toDartString();
+  return result == nullptr ? '' : result.cast<Utf8>().toDartString();
 }
 
 /// Get the remote's url.
 String url(Pointer<git_remote> remote) {
-  return libgit2.git_remote_url(remote).toDartString();
+  return libgit2.git_remote_url(remote).cast<Utf8>().toDartString();
 }
 
 /// Get the remote's url for pushing.
@@ -234,7 +235,7 @@ String url(Pointer<git_remote> remote) {
 /// Returns empty string if no special url for pushing is set.
 String pushUrl(Pointer<git_remote> remote) {
   final result = libgit2.git_remote_pushurl(remote);
-  return result == nullptr ? '' : result.toDartString();
+  return result == nullptr ? '' : result.cast<Utf8>().toDartString();
 }
 
 /// Get the number of refspecs for a remote.
@@ -255,7 +256,8 @@ List<String> fetchRefspecs(Pointer<git_remote> remote) {
   libgit2.git_remote_get_fetch_refspecs(out, remote);
 
   final result = <String>[
-    for (var i = 0; i < out.ref.count; i++) out.ref.strings[i].toDartString()
+    for (var i = 0; i < out.ref.count; i++)
+      out.ref.strings[i].cast<Utf8>().toDartString()
   ];
 
   calloc.free(out);
@@ -269,7 +271,8 @@ List<String> pushRefspecs(Pointer<git_remote> remote) {
   libgit2.git_remote_get_push_refspecs(out, remote);
 
   final result = <String>[
-    for (var i = 0; i < out.ref.count; i++) out.ref.strings[i].toDartString()
+    for (var i = 0; i < out.ref.count; i++)
+      out.ref.strings[i].cast<Utf8>().toDartString()
   ];
 
   calloc.free(out);
@@ -288,8 +291,8 @@ void addFetch({
   required String remote,
   required String refspec,
 }) {
-  final remoteC = remote.toChar();
-  final refspecC = refspec.toChar();
+  final remoteC = remote.toNativeUtf8().cast<Char>();
+  final refspecC = refspec.toNativeUtf8().cast<Char>();
   final error = libgit2.git_remote_add_fetch(repoPointer, remoteC, refspecC);
 
   calloc.free(remoteC);
@@ -311,8 +314,8 @@ void addPush({
   required String remote,
   required String refspec,
 }) {
-  final remoteC = remote.toChar();
-  final refspecC = refspec.toChar();
+  final remoteC = remote.toNativeUtf8().cast<Char>();
+  final refspecC = refspec.toNativeUtf8().cast<Char>();
   final error = libgit2.git_remote_add_push(repoPointer, remoteC, refspecC);
 
   calloc.free(remoteC);
@@ -390,11 +393,12 @@ List<Map<String, Object?>> lsRemotes(Pointer<git_remote> remote) {
 
     remote['local'] = local;
     remote['loid'] = local ? Oid.fromRaw(out[0][i].ref.loid) : null;
-    remote['name'] =
-        out[0][i].ref.name == nullptr ? '' : out[0][i].ref.name.toDartString();
+    remote['name'] = out[0][i].ref.name == nullptr
+        ? ''
+        : out[0][i].ref.name.cast<Utf8>().toDartString();
     remote['symref'] = out[0][i].ref.symref_target == nullptr
         ? ''
-        : out[0][i].ref.symref_target.toDartString();
+        : out[0][i].ref.symref_target.cast<Utf8>().toDartString();
     remote['oid'] = Oid.fromRaw(out[0][i].ref.oid);
 
     result.add(remote);
@@ -421,7 +425,8 @@ void fetch({
   String? proxyOption,
 }) {
   final refspecsC = calloc<git_strarray>();
-  final refspecsPointers = refspecs.map((e) => e.toChar()).toList();
+  final refspecsPointers =
+      refspecs.map((e) => e.toNativeUtf8().cast<Char>()).toList();
   final strArray = calloc<Pointer<Char>>(refspecs.length);
 
   for (var i = 0; i < refspecs.length; i++) {
@@ -430,7 +435,7 @@ void fetch({
 
   refspecsC.ref.count = refspecs.length;
   refspecsC.ref.strings = strArray;
-  final reflogMessageC = reflogMessage?.toChar() ?? nullptr;
+  final reflogMessageC = reflogMessage?.toNativeUtf8().cast<Char>() ?? nullptr;
 
   final proxyOptions = _proxyOptionsInit(proxyOption);
 
@@ -476,7 +481,8 @@ void push({
   String? proxyOption,
 }) {
   final refspecsC = calloc<git_strarray>();
-  final refspecsPointers = refspecs.map((e) => e.toChar()).toList();
+  final refspecsPointers =
+      refspecs.map((e) => e.toNativeUtf8().cast<Char>()).toList();
   final strArray = calloc<Pointer<Char>>(refspecs.length);
 
   for (var i = 0; i < refspecs.length; i++) {
@@ -566,7 +572,7 @@ Pointer<git_proxy_options> _proxyOptionsInit(String? proxyOption) {
     proxyOptions.ref.type = git_proxy_t.GIT_PROXY_AUTO;
   } else {
     proxyOptions.ref.type = git_proxy_t.GIT_PROXY_SPECIFIED;
-    proxyOptions.ref.url = proxyOption.toChar();
+    proxyOptions.ref.url = proxyOption.toNativeUtf8().cast<Char>();
   }
 
   return proxyOptions;
diff --git a/lib/src/bindings/remote_callbacks.dart b/lib/src/bindings/remote_callbacks.dart
index d1f0e1b..c0ee976 100644
--- a/lib/src/bindings/remote_callbacks.dart
+++ b/lib/src/bindings/remote_callbacks.dart
@@ -8,7 +8,6 @@ import 'package:libgit2dart/src/bindings/libgit2_bindings.dart';
 import 'package:libgit2dart/src/bindings/remote.dart' as remote_bindings;
 import 'package:libgit2dart/src/bindings/repository.dart'
     as repository_bindings;
-import 'package:libgit2dart/src/extensions.dart';
 import 'package:libgit2dart/src/util.dart';
 
 class RemoteCallbacks {
@@ -34,7 +33,7 @@ class RemoteCallbacks {
     int length,
     Pointer<Void> payload,
   ) {
-    sidebandProgress!(progressOutput.toDartString(length: length));
+    sidebandProgress!(progressOutput.cast<Utf8>().toDartString(length: length));
     return 0;
   }
 
@@ -48,7 +47,7 @@ class RemoteCallbacks {
     Pointer<git_oid> newOid,
     Pointer<Void> payload,
   ) {
-    updateTips!(refname.toDartString(), Oid(oldOid), Oid(newOid));
+    updateTips!(refname.cast<Utf8>().toDartString(), Oid(oldOid), Oid(newOid));
     return 0;
   }
 
@@ -63,8 +62,9 @@ class RemoteCallbacks {
     Pointer<Char> message,
     Pointer<Void> payload,
   ) {
-    final messageResult = message == nullptr ? '' : message.toDartString();
-    pushUpdateReference!(refname.toDartString(), messageResult);
+    final messageResult =
+        message == nullptr ? '' : message.cast<Utf8>().toDartString();
+    pushUpdateReference!(refname.cast<Utf8>().toDartString(), messageResult);
     return 0;
   }
 
@@ -155,7 +155,7 @@ class RemoteCallbacks {
     if (payload.cast<Char>().value == 2) {
       libgit2.git_error_set_str(
         git_error_t.GIT_ERROR_INVALID,
-        'Incorrect credentials.'.toChar(),
+        'Incorrect credentials.'.toNativeUtf8().cast<Char>(),
       );
       throw LibGit2Error(libgit2.git_error_last());
     }
@@ -165,7 +165,7 @@ class RemoteCallbacks {
     if (allowedTypes & credentialType.value != credentialType.value) {
       libgit2.git_error_set_str(
         git_error_t.GIT_ERROR_INVALID,
-        'Invalid credential type $credentialType'.toChar(),
+        'Invalid credential type $credentialType'.toNativeUtf8().cast<Char>(),
       );
       throw LibGit2Error(libgit2.git_error_last());
     }
diff --git a/lib/src/bindings/repository.dart b/lib/src/bindings/repository.dart
index a1d0a79..44a8745 100644
--- a/lib/src/bindings/repository.dart
+++ b/lib/src/bindings/repository.dart
@@ -5,7 +5,6 @@ import 'package:libgit2dart/src/bindings/libgit2_bindings.dart';
 import 'package:libgit2dart/src/bindings/remote_callbacks.dart';
 import 'package:libgit2dart/src/callbacks.dart';
 import 'package:libgit2dart/src/error.dart';
-import 'package:libgit2dart/src/extensions.dart';
 import 'package:libgit2dart/src/remote.dart';
 import 'package:libgit2dart/src/repository.dart';
 import 'package:libgit2dart/src/util.dart';
@@ -18,7 +17,7 @@ import 'package:libgit2dart/src/util.dart';
 /// Throws a [LibGit2Error] if error occured.
 Pointer<git_repository> open(String path) {
   final out = calloc<Pointer<git_repository>>();
-  final pathC = path.toChar();
+  final pathC = path.toNativeUtf8().cast<Char>();
   final error = libgit2.git_repository_open(out, pathC);
 
   final result = out.value;
@@ -45,15 +44,15 @@ String discover({
   String? ceilingDirs,
 }) {
   final out = calloc<git_buf>();
-  final startPathC = startPath.toChar();
-  final ceilingDirsC = ceilingDirs?.toChar() ?? nullptr;
+  final startPathC = startPath.toNativeUtf8().cast<Char>();
+  final ceilingDirsC = ceilingDirs?.toNativeUtf8().cast<Char>() ?? nullptr;
 
   libgit2.git_repository_discover(out, startPathC, 0, ceilingDirsC);
 
   calloc.free(startPathC);
   calloc.free(ceilingDirsC);
 
-  final result = out.ref.ptr.toDartString(length: out.ref.size);
+  final result = out.ref.ptr.cast<Utf8>().toDartString(length: out.ref.size);
 
   libgit2.git_buf_dispose(out);
   calloc.free(out);
@@ -76,12 +75,12 @@ Pointer<git_repository> init({
   String? originUrl,
 }) {
   final out = calloc<Pointer<git_repository>>();
-  final pathC = path.toChar();
-  final workdirPathC = workdirPath?.toChar() ?? nullptr;
-  final descriptionC = description?.toChar() ?? nullptr;
-  final templatePathC = templatePath?.toChar() ?? nullptr;
-  final initialHeadC = initialHead?.toChar() ?? nullptr;
-  final originUrlC = originUrl?.toChar() ?? nullptr;
+  final pathC = path.toNativeUtf8().cast<Char>();
+  final workdirPathC = workdirPath?.toNativeUtf8().cast<Char>() ?? nullptr;
+  final descriptionC = description?.toNativeUtf8().cast<Char>() ?? nullptr;
+  final templatePathC = templatePath?.toNativeUtf8().cast<Char>() ?? nullptr;
+  final initialHeadC = initialHead?.toNativeUtf8().cast<Char>() ?? nullptr;
+  final originUrlC = originUrl?.toNativeUtf8().cast<Char>() ?? nullptr;
   final opts = calloc<git_repository_init_options>();
   libgit2.git_repository_init_options_init(
     opts,
@@ -130,9 +129,10 @@ Pointer<git_repository> clone({
   required Callbacks callbacks,
 }) {
   final out = calloc<Pointer<git_repository>>();
-  final urlC = url.toChar();
-  final localPathC = localPath.toChar();
-  final checkoutBranchC = checkoutBranch?.toChar() ?? nullptr;
+  final urlC = url.toNativeUtf8().cast<Char>();
+  final localPathC = localPath.toNativeUtf8().cast<Char>();
+  final checkoutBranchC =
+      checkoutBranch?.toNativeUtf8().cast<Char>() ?? nullptr;
 
   final cloneOptions = calloc<git_clone_options>();
   libgit2.git_clone_options_init(cloneOptions, GIT_CLONE_OPTIONS_VERSION);
@@ -187,7 +187,7 @@ Pointer<git_repository> clone({
 /// Returns the path to the `.git` folder for normal repositories or the
 /// repository itself for bare repositories.
 String path(Pointer<git_repository> repo) {
-  return libgit2.git_repository_path(repo).toDartString();
+  return libgit2.git_repository_path(repo).cast<Utf8>().toDartString();
 }
 
 /// Get the path of the shared common directory for this repository.
@@ -196,7 +196,7 @@ String path(Pointer<git_repository> repo) {
 /// If the repository is a worktree, it is the parent repo's `.git` folder.
 /// Otherwise, it is the `.git` folder.
 String commonDir(Pointer<git_repository> repo) {
-  return libgit2.git_repository_commondir(repo).toDartString();
+  return libgit2.git_repository_commondir(repo).cast<Utf8>().toDartString();
 }
 
 /// Get the currently active namespace for this repository.
@@ -205,7 +205,11 @@ String commonDir(Pointer<git_repository> repo) {
 /// empty string is returned.
 String getNamespace(Pointer<git_repository> repo) {
   final result = libgit2.git_repository_get_namespace(repo);
-  return result == nullptr ? '' : result.toDartString();
+  if (result == nullptr) {
+    return '';
+  } else {
+    return result.cast<Utf8>().toDartString();
+  }
 }
 
 /// Sets the active namespace for this repository.
@@ -219,7 +223,7 @@ void setNamespace({
   required Pointer<git_repository> repoPointer,
   String? namespace,
 }) {
-  final namespaceC = namespace?.toChar() ?? nullptr;
+  final namespaceC = namespace?.toNativeUtf8().cast<Char>() ?? nullptr;
   libgit2.git_repository_set_namespace(repoPointer, namespaceC);
   calloc.free(namespaceC);
 }
@@ -306,8 +310,8 @@ void setIdentity({
   String? name,
   String? email,
 }) {
-  final nameC = name?.toChar() ?? nullptr;
-  final emailC = email?.toChar() ?? nullptr;
+  final nameC = name?.toNativeUtf8().cast<Char>() ?? nullptr;
+  final emailC = email?.toNativeUtf8().cast<Char>() ?? nullptr;
 
   libgit2.git_repository_set_ident(repoPointer, nameC, emailC);
 
@@ -327,8 +331,8 @@ List<String> identity(Pointer<git_repository> repo) {
   if (name.value == nullptr && email.value == nullptr) {
     return identity;
   } else {
-    identity.add(name.value.toDartString());
-    identity.add(email.value.toDartString());
+    identity.add(name.value.cast<Utf8>().toDartString());
+    identity.add(email.value.cast<Utf8>().toDartString());
   }
 
   calloc.free(name);
@@ -412,7 +416,7 @@ String message(Pointer<git_repository> repo) {
   final out = calloc<git_buf>();
   final error = libgit2.git_repository_message(out, repo);
 
-  final result = out.ref.ptr.toDartString(length: out.ref.size);
+  final result = out.ref.ptr.cast<Utf8>().toDartString(length: out.ref.size);
 
   libgit2.git_buf_dispose(out);
   calloc.free(out);
@@ -490,7 +494,7 @@ void setHead({
   required Pointer<git_repository> repoPointer,
   required String refname,
 }) {
-  final refnameC = refname.toChar();
+  final refnameC = refname.toNativeUtf8().cast<Char>();
   final error = libgit2.git_repository_set_head(repoPointer, refnameC);
 
   calloc.free(refnameC);
@@ -541,7 +545,7 @@ void setWorkdir({
   required String path,
   required bool updateGitlink,
 }) {
-  final workdirC = path.toChar();
+  final workdirC = path.toNativeUtf8().cast<Char>();
   final updateGitlinkC = updateGitlink ? 1 : 0;
   final error = libgit2.git_repository_set_workdir(
     repoPointer,
@@ -577,7 +581,12 @@ void stateCleanup(Pointer<git_repository> repo) {
 /// If the repository is bare, this function will always return empty string.
 String workdir(Pointer<git_repository> repo) {
   final result = libgit2.git_repository_workdir(repo);
-  return result == nullptr ? '' : result.toDartString();
+
+  if (result == nullptr) {
+    return '';
+  } else {
+    return result.cast<Utf8>().toDartString();
+  }
 }
 
 /// Free a previously allocated repository.
diff --git a/lib/src/bindings/reset.dart b/lib/src/bindings/reset.dart
index cca5dba..e1c89ec 100644
--- a/lib/src/bindings/reset.dart
+++ b/lib/src/bindings/reset.dart
@@ -3,7 +3,6 @@ import 'dart:ffi';
 import 'package:ffi/ffi.dart';
 import 'package:libgit2dart/src/bindings/libgit2_bindings.dart';
 import 'package:libgit2dart/src/error.dart';
-import 'package:libgit2dart/src/extensions.dart';
 import 'package:libgit2dart/src/util.dart';
 
 /// Sets the current head to the specified commit oid and optionally resets the
@@ -41,7 +40,8 @@ void resetDefault({
   required List<String> pathspec,
 }) {
   final pathspecC = calloc<git_strarray>();
-  final pathPointers = pathspec.map((e) => e.toChar()).toList();
+  final pathPointers =
+      pathspec.map((e) => e.toNativeUtf8().cast<Char>()).toList();
   final strArray = calloc<Pointer<Char>>(pathspec.length);
 
   for (var i = 0; i < pathspec.length; i++) {
diff --git a/lib/src/bindings/revparse.dart b/lib/src/bindings/revparse.dart
index 3452687..acf14c8 100644
--- a/lib/src/bindings/revparse.dart
+++ b/lib/src/bindings/revparse.dart
@@ -3,7 +3,6 @@ import 'dart:ffi';
 import 'package:ffi/ffi.dart';
 import 'package:libgit2dart/src/bindings/libgit2_bindings.dart';
 import 'package:libgit2dart/src/error.dart';
-import 'package:libgit2dart/src/extensions.dart';
 import 'package:libgit2dart/src/util.dart';
 
 /// Parse a revision string for from, to, and intent.
@@ -17,7 +16,7 @@ Pointer<git_revspec> revParse({
   required String spec,
 }) {
   final out = calloc<git_revspec>();
-  final specC = spec.toChar();
+  final specC = spec.toNativeUtf8().cast<Char>();
 
   final error = libgit2.git_revparse(out, repoPointer, specC);
 
@@ -43,7 +42,7 @@ Pointer<git_object> revParseSingle({
   required String spec,
 }) {
   final out = calloc<Pointer<git_object>>();
-  final specC = spec.toChar();
+  final specC = spec.toNativeUtf8().cast<Char>();
 
   final error = libgit2.git_revparse_single(out, repoPointer, specC);
 
@@ -77,7 +76,7 @@ List<Pointer> revParseExt({
 }) {
   final objectOut = calloc<Pointer<git_object>>();
   final referenceOut = calloc<Pointer<git_reference>>();
-  final specC = spec.toChar();
+  final specC = spec.toNativeUtf8().cast<Char>();
 
   final error = libgit2.git_revparse_ext(
     objectOut,
@@ -86,7 +85,8 @@ List<Pointer> revParseExt({
     specC,
   );
 
-  final result = <Pointer>[objectOut.value];
+  final result = <Pointer>[];
+  result.add(objectOut.value);
   if (referenceOut.value != nullptr) {
     result.add(referenceOut.value);
   }
diff --git a/lib/src/bindings/revwalk.dart b/lib/src/bindings/revwalk.dart
index 93d9bf6..00297ed 100644
--- a/lib/src/bindings/revwalk.dart
+++ b/lib/src/bindings/revwalk.dart
@@ -4,7 +4,6 @@ import 'package:ffi/ffi.dart';
 import 'package:libgit2dart/src/bindings/commit.dart' as commit_bindings;
 import 'package:libgit2dart/src/bindings/libgit2_bindings.dart';
 import 'package:libgit2dart/src/error.dart';
-import 'package:libgit2dart/src/extensions.dart';
 import 'package:libgit2dart/src/util.dart';
 
 /// Allocate a new revision walker to iterate through a repo. The returned
@@ -82,7 +81,7 @@ void pushGlob({
   required Pointer<git_revwalk> walkerPointer,
   required String glob,
 }) {
-  final globC = glob.toChar();
+  final globC = glob.toNativeUtf8().cast<Char>();
   libgit2.git_revwalk_push_glob(walkerPointer, globC);
   calloc.free(globC);
 }
@@ -100,7 +99,7 @@ void pushRef({
   required Pointer<git_revwalk> walkerPointer,
   required String refName,
 }) {
-  final refNameC = refName.toChar();
+  final refNameC = refName.toNativeUtf8().cast<Char>();
   final error = libgit2.git_revwalk_push_ref(walkerPointer, refNameC);
 
   calloc.free(refNameC);
@@ -120,7 +119,7 @@ void pushRange({
   required Pointer<git_revwalk> walkerPointer,
   required String range,
 }) {
-  final rangeC = range.toChar();
+  final rangeC = range.toNativeUtf8().cast<Char>();
   final error = libgit2.git_revwalk_push_range(walkerPointer, rangeC);
 
   calloc.free(rangeC);
@@ -200,7 +199,7 @@ void hideGlob({
   required Pointer<git_revwalk> walkerPointer,
   required String glob,
 }) {
-  final globC = glob.toChar();
+  final globC = glob.toNativeUtf8().cast<Char>();
   libgit2.git_revwalk_hide_glob(walkerPointer, globC);
   calloc.free(globC);
 }
@@ -218,7 +217,7 @@ void hideRef({
   required Pointer<git_revwalk> walkerPointer,
   required String refName,
 }) {
-  final refNameC = refName.toChar();
+  final refNameC = refName.toNativeUtf8().cast<Char>();
   final error = libgit2.git_revwalk_hide_ref(walkerPointer, refNameC);
 
   calloc.free(refNameC);
diff --git a/lib/src/bindings/signature.dart b/lib/src/bindings/signature.dart
index 81b260b..5a02449 100644
--- a/lib/src/bindings/signature.dart
+++ b/lib/src/bindings/signature.dart
@@ -3,7 +3,6 @@ import 'dart:ffi';
 import 'package:ffi/ffi.dart';
 import 'package:libgit2dart/src/bindings/libgit2_bindings.dart';
 import 'package:libgit2dart/src/error.dart';
-import 'package:libgit2dart/src/extensions.dart';
 import 'package:libgit2dart/src/util.dart';
 
 /// Create a new action signature. The returned signature must be freed with
@@ -20,8 +19,8 @@ Pointer<git_signature> create({
   required int offset,
 }) {
   final out = calloc<Pointer<git_signature>>();
-  final nameC = name.toChar();
-  final emailC = email.toChar();
+  final nameC = name.toNativeUtf8().cast<Char>();
+  final emailC = email.toNativeUtf8().cast<Char>();
   final error = libgit2.git_signature_new(out, nameC, emailC, time, offset);
 
   final result = out.value;
@@ -43,8 +42,8 @@ Pointer<git_signature> create({
 /// Throws a [LibGit2Error] if error occured.
 Pointer<git_signature> now({required String name, required String email}) {
   final out = calloc<Pointer<git_signature>>();
-  final nameC = name.toChar();
-  final emailC = email.toChar();
+  final nameC = name.toNativeUtf8().cast<Char>();
+  final emailC = email.toNativeUtf8().cast<Char>();
   final error = libgit2.git_signature_now(out, nameC, emailC);
 
   final result = out.value;
diff --git a/lib/src/bindings/stash.dart b/lib/src/bindings/stash.dart
index 91cc4c5..bfb9a15 100644
--- a/lib/src/bindings/stash.dart
+++ b/lib/src/bindings/stash.dart
@@ -4,7 +4,6 @@ import 'package:ffi/ffi.dart';
 import 'package:libgit2dart/src/bindings/checkout.dart' as checkout_bindings;
 import 'package:libgit2dart/src/bindings/libgit2_bindings.dart';
 import 'package:libgit2dart/src/error.dart';
-import 'package:libgit2dart/src/extensions.dart';
 import 'package:libgit2dart/src/oid.dart';
 import 'package:libgit2dart/src/stash.dart';
 import 'package:libgit2dart/src/util.dart';
@@ -19,7 +18,7 @@ Pointer<git_oid> save({
   required int flags,
 }) {
   final out = calloc<git_oid>();
-  final messageC = message?.toChar() ?? nullptr;
+  final messageC = message?.toNativeUtf8().cast<Char>() ?? nullptr;
   final error = libgit2.git_stash_save(
     out,
     repoPointer,
@@ -149,7 +148,11 @@ int _stashCb(
   Pointer<Void> payload,
 ) {
   _stashList.add(
-    Stash(index: index, message: message.toDartString(), oid: Oid(oid)),
+    Stash(
+      index: index,
+      message: message.cast<Utf8>().toDartString(),
+      oid: Oid(oid),
+    ),
   );
   return 0;
 }
diff --git a/lib/src/bindings/status.dart b/lib/src/bindings/status.dart
index 57e33cf..29ddf58 100644
--- a/lib/src/bindings/status.dart
+++ b/lib/src/bindings/status.dart
@@ -4,7 +4,6 @@ import 'package:ffi/ffi.dart';
 import 'package:libgit2dart/libgit2dart.dart';
 import 'package:libgit2dart/src/bindings/libgit2_bindings.dart';
 import 'package:libgit2dart/src/error.dart';
-import 'package:libgit2dart/src/extensions.dart';
 import 'package:libgit2dart/src/util.dart';
 
 /// Gather file status information and populate the git_status_list. The
@@ -64,7 +63,7 @@ Pointer<git_status_entry> getByIndex({
 /// Throws a [LibGit2Error] if error occured.
 int file({required Pointer<git_repository> repoPointer, required String path}) {
   final out = calloc<UnsignedInt>();
-  final pathC = path.toChar();
+  final pathC = path.toNativeUtf8().cast<Char>();
   final error = libgit2.git_status_file(out, repoPointer, pathC);
 
   final result = out.value;
diff --git a/lib/src/bindings/submodule.dart b/lib/src/bindings/submodule.dart
index ce9755c..186829b 100644
--- a/lib/src/bindings/submodule.dart
+++ b/lib/src/bindings/submodule.dart
@@ -5,7 +5,6 @@ import 'package:libgit2dart/src/bindings/libgit2_bindings.dart';
 import 'package:libgit2dart/src/bindings/remote_callbacks.dart';
 import 'package:libgit2dart/src/callbacks.dart';
 import 'package:libgit2dart/src/error.dart';
-import 'package:libgit2dart/src/extensions.dart';
 import 'package:libgit2dart/src/util.dart';
 
 /// List of submodule paths.
@@ -51,7 +50,7 @@ Pointer<git_submodule> lookup({
   required String name,
 }) {
   final out = calloc<Pointer<git_submodule>>();
-  final nameC = name.toChar();
+  final nameC = name.toNativeUtf8().cast<Char>();
 
   final error = libgit2.git_submodule_lookup(out, repoPointer, nameC);
 
@@ -160,8 +159,8 @@ Pointer<git_submodule> addSetup({
   bool useGitlink = true,
 }) {
   final out = calloc<Pointer<git_submodule>>();
-  final urlC = url.toChar();
-  final pathC = path.toChar();
+  final urlC = url.toNativeUtf8().cast<Char>();
+  final pathC = path.toNativeUtf8().cast<Char>();
   final useGitlinkC = useGitlink ? 1 : 0;
   final error = libgit2.git_submodule_add_setup(
     out,
@@ -234,7 +233,7 @@ int status({
   required int ignore,
 }) {
   final out = calloc<UnsignedInt>();
-  final nameC = name.toChar();
+  final nameC = name.toNativeUtf8().cast<Char>();
   libgit2.git_submodule_status(out, repoPointer, nameC, ignore);
 
   final result = out.value;
@@ -270,7 +269,7 @@ void reload({
 
 /// Get the name of submodule.
 String name(Pointer<git_submodule> submodule) {
-  return libgit2.git_submodule_name(submodule).toDartString();
+  return libgit2.git_submodule_name(submodule).cast<Utf8>().toDartString();
 }
 
 /// Get the path to the submodule.
@@ -278,12 +277,12 @@ String name(Pointer<git_submodule> submodule) {
 /// The path is almost always the same as the submodule name, but the two
 /// are actually not required to match.
 String path(Pointer<git_submodule> submodule) {
-  return libgit2.git_submodule_path(submodule).toDartString();
+  return libgit2.git_submodule_path(submodule).cast<Utf8>().toDartString();
 }
 
 /// Get the URL for the submodule.
 String url(Pointer<git_submodule> submodule) {
-  return libgit2.git_submodule_url(submodule).toDartString();
+  return libgit2.git_submodule_url(submodule).cast<Utf8>().toDartString();
 }
 
 /// Set the URL for the submodule in the configuration.
@@ -295,8 +294,8 @@ void setUrl({
   required String name,
   required String url,
 }) {
-  final nameC = name.toChar();
-  final urlC = url.toChar();
+  final nameC = name.toNativeUtf8().cast<Char>();
+  final urlC = url.toNativeUtf8().cast<Char>();
 
   libgit2.git_submodule_set_url(repoPointer, nameC, urlC);
 
@@ -307,7 +306,7 @@ void setUrl({
 /// Get the branch for the submodule.
 String branch(Pointer<git_submodule> submodule) {
   final result = libgit2.git_submodule_branch(submodule);
-  return result == nullptr ? '' : result.toDartString();
+  return result == nullptr ? '' : result.cast<Utf8>().toDartString();
 }
 
 /// Set the branch for the submodule in the configuration.
@@ -319,8 +318,8 @@ void setBranch({
   required String name,
   required String branch,
 }) {
-  final nameC = name.toChar();
-  final branchC = branch.toChar();
+  final nameC = name.toNativeUtf8().cast<Char>();
+  final branchC = branch.toNativeUtf8().cast<Char>();
 
   libgit2.git_submodule_set_branch(repoPointer, nameC, branchC);
 
@@ -370,7 +369,7 @@ void setIgnore({
   required String name,
   required int ignore,
 }) {
-  final nameC = name.toChar();
+  final nameC = name.toNativeUtf8().cast<Char>();
   libgit2.git_submodule_set_ignore(repoPointer, nameC, ignore);
   calloc.free(nameC);
 }
@@ -390,7 +389,7 @@ void setUpdateRule({
   required String name,
   required int update,
 }) {
-  final nameC = name.toChar();
+  final nameC = name.toNativeUtf8().cast<Char>();
   libgit2.git_submodule_set_update(repoPointer, nameC, update);
   calloc.free(nameC);
 }
diff --git a/lib/src/bindings/tag.dart b/lib/src/bindings/tag.dart
index 3c6efff..6201a1f 100644
--- a/lib/src/bindings/tag.dart
+++ b/lib/src/bindings/tag.dart
@@ -3,7 +3,6 @@ import 'dart:ffi';
 import 'package:ffi/ffi.dart';
 import 'package:libgit2dart/src/bindings/libgit2_bindings.dart';
 import 'package:libgit2dart/src/error.dart';
-import 'package:libgit2dart/src/extensions.dart';
 import 'package:libgit2dart/src/util.dart';
 
 /// Fill a list with all the tags in the repository.
@@ -13,16 +12,16 @@ List<String> list(Pointer<git_repository> repo) {
   final out = calloc<git_strarray>();
   final error = libgit2.git_tag_list(out, repo);
 
+  final result = <String>[];
+
   if (error < 0) {
     calloc.free(out);
     throw LibGit2Error(libgit2.git_error_last());
   } else {
-    final result = <String>[
-      for (var i = 0; i < out.ref.count; i++) out.ref.strings[i].toDartString()
-    ];
-
+    for (var i = 0; i < out.ref.count; i++) {
+      result.add(out.ref.strings[i].cast<Utf8>().toDartString());
+    }
     calloc.free(out);
-
     return result;
   }
 }
@@ -81,12 +80,13 @@ Pointer<git_oid> targetOid(Pointer<git_tag> tag) =>
 Pointer<git_oid> id(Pointer<git_tag> tag) => libgit2.git_tag_id(tag);
 
 /// Get the name of a tag.
-String name(Pointer<git_tag> tag) => libgit2.git_tag_name(tag).toDartString();
+String name(Pointer<git_tag> tag) =>
+    libgit2.git_tag_name(tag).cast<Utf8>().toDartString();
 
 /// Get the message of a tag.
 String message(Pointer<git_tag> tag) {
   final result = libgit2.git_tag_message(tag);
-  return result == nullptr ? '' : result.toDartString();
+  return result == nullptr ? '' : result.cast<Utf8>().toDartString();
 }
 
 /// Get the tagger (author) of a tag. The returned signature must be freed.
@@ -115,8 +115,8 @@ Pointer<git_oid> createAnnotated({
   required bool force,
 }) {
   final out = calloc<git_oid>();
-  final tagNameC = tagName.toChar();
-  final messageC = message.toChar();
+  final tagNameC = tagName.toNativeUtf8().cast<Char>();
+  final messageC = message.toNativeUtf8().cast<Char>();
   final error = libgit2.git_tag_create(
     out,
     repoPointer,
@@ -155,7 +155,7 @@ Pointer<git_oid> createLightweight({
   required bool force,
 }) {
   final out = calloc<git_oid>();
-  final tagNameC = tagName.toChar();
+  final tagNameC = tagName.toNativeUtf8().cast<Char>();
   final error = libgit2.git_tag_create_lightweight(
     out,
     repoPointer,
@@ -183,7 +183,7 @@ void delete({
   required Pointer<git_repository> repoPointer,
   required String tagName,
 }) {
-  final tagNameC = tagName.toChar();
+  final tagNameC = tagName.toNativeUtf8().cast<Char>();
   final error = libgit2.git_tag_delete(repoPointer, tagNameC);
 
   calloc.free(tagNameC);
diff --git a/lib/src/bindings/tree.dart b/lib/src/bindings/tree.dart
index fa536b3..ca18ba4 100644
--- a/lib/src/bindings/tree.dart
+++ b/lib/src/bindings/tree.dart
@@ -3,7 +3,6 @@ import 'dart:ffi';
 import 'package:ffi/ffi.dart';
 import 'package:libgit2dart/src/bindings/libgit2_bindings.dart';
 import 'package:libgit2dart/src/error.dart';
-import 'package:libgit2dart/src/extensions.dart';
 import 'package:libgit2dart/src/util.dart';
 
 /// Get the id of a tree.
@@ -60,7 +59,7 @@ Pointer<git_tree_entry> getByName({
   required Pointer<git_tree> treePointer,
   required String filename,
 }) {
-  final filenameC = filename.toChar();
+  final filenameC = filename.toNativeUtf8().cast<Char>();
   final result = libgit2.git_tree_entry_byname(treePointer, filenameC);
 
   calloc.free(filenameC);
@@ -84,7 +83,7 @@ Pointer<git_tree_entry> getByPath({
   required String path,
 }) {
   final out = calloc<Pointer<git_tree_entry>>();
-  final pathC = path.toChar();
+  final pathC = path.toNativeUtf8().cast<Char>();
   final error = libgit2.git_tree_entry_bypath(out, rootPointer, pathC);
 
   final result = out.value;
@@ -108,7 +107,7 @@ Pointer<git_oid> entryId(Pointer<git_tree_entry> entry) =>
 
 /// Get the filename of a tree entry.
 String entryName(Pointer<git_tree_entry> entry) =>
-    libgit2.git_tree_entry_name(entry).toDartString();
+    libgit2.git_tree_entry_name(entry).cast<Utf8>().toDartString();
 
 /// Get the UNIX file attributes of a tree entry.
 int entryFilemode(Pointer<git_tree_entry> entry) =>
diff --git a/lib/src/bindings/treebuilder.dart b/lib/src/bindings/treebuilder.dart
index 5819cdb..9ab87aa 100644
--- a/lib/src/bindings/treebuilder.dart
+++ b/lib/src/bindings/treebuilder.dart
@@ -3,7 +3,6 @@ import 'dart:ffi';
 import 'package:ffi/ffi.dart';
 import 'package:libgit2dart/src/bindings/libgit2_bindings.dart';
 import 'package:libgit2dart/src/error.dart';
-import 'package:libgit2dart/src/extensions.dart';
 import 'package:libgit2dart/src/util.dart';
 
 /// Create a new tree builder. The returned tree builder must be freed with
@@ -54,7 +53,7 @@ Pointer<git_tree_entry> getByFilename({
   required Pointer<git_treebuilder> builderPointer,
   required String filename,
 }) {
-  final filenameC = filename.toChar();
+  final filenameC = filename.toNativeUtf8().cast<Char>();
   final result = libgit2.git_treebuilder_get(builderPointer, filenameC);
 
   calloc.free(filenameC);
@@ -83,7 +82,7 @@ void add({
   required Pointer<git_oid> oidPointer,
   required int filemode,
 }) {
-  final filenameC = filename.toChar();
+  final filenameC = filename.toNativeUtf8().cast<Char>();
   final error = libgit2.git_treebuilder_insert(
     nullptr,
     builderPointer,
@@ -106,7 +105,7 @@ void remove({
   required Pointer<git_treebuilder> builderPointer,
   required String filename,
 }) {
-  final filenameC = filename.toChar();
+  final filenameC = filename.toNativeUtf8().cast<Char>();
   final error = libgit2.git_treebuilder_remove(builderPointer, filenameC);
 
   calloc.free(filenameC);
diff --git a/lib/src/bindings/worktree.dart b/lib/src/bindings/worktree.dart
index 663c1f2..2daa0ae 100644
--- a/lib/src/bindings/worktree.dart
+++ b/lib/src/bindings/worktree.dart
@@ -4,7 +4,6 @@ import 'package:ffi/ffi.dart';
 import 'package:libgit2dart/libgit2dart.dart';
 import 'package:libgit2dart/src/bindings/libgit2_bindings.dart';
 import 'package:libgit2dart/src/error.dart';
-import 'package:libgit2dart/src/extensions.dart';
 import 'package:libgit2dart/src/util.dart';
 
 /// Add a new working tree. The returned worktree must be freed with [free].
@@ -21,8 +20,8 @@ Pointer<git_worktree> create({
   Pointer<git_reference>? refPointer,
 }) {
   final out = calloc<Pointer<git_worktree>>();
-  final nameC = name.toChar();
-  final pathC = path.toChar();
+  final nameC = name.toNativeUtf8().cast<Char>();
+  final pathC = path.toNativeUtf8().cast<Char>();
 
   final opts = calloc<git_worktree_add_options>();
   libgit2.git_worktree_add_options_init(opts, GIT_WORKTREE_ADD_OPTIONS_VERSION);
@@ -57,7 +56,7 @@ Pointer<git_worktree> lookup({
   required String name,
 }) {
   final out = calloc<Pointer<git_worktree>>();
-  final nameC = name.toChar();
+  final nameC = name.toNativeUtf8().cast<Char>();
   final error = libgit2.git_worktree_lookup(out, repoPointer, nameC);
 
   final result = out.value;
@@ -112,7 +111,8 @@ List<String> list(Pointer<git_repository> repo) {
     throw LibGit2Error(libgit2.git_error_last());
   } else {
     final result = <String>[
-      for (var i = 0; i < out.ref.count; i++) out.ref.strings[i].toDartString()
+      for (var i = 0; i < out.ref.count; i++)
+        out.ref.strings[i].cast<Utf8>().toDartString()
     ];
 
     calloc.free(out);
@@ -123,12 +123,12 @@ List<String> list(Pointer<git_repository> repo) {
 
 /// Retrieve the name of the worktree.
 String name(Pointer<git_worktree> wt) {
-  return libgit2.git_worktree_name(wt).toDartString();
+  return libgit2.git_worktree_name(wt).cast<Utf8>().toDartString();
 }
 
 /// Retrieve the filesystem path for the worktree.
 String path(Pointer<git_worktree> wt) {
-  return libgit2.git_worktree_path(wt).toDartString();
+  return libgit2.git_worktree_path(wt).cast<Utf8>().toDartString();
 }
 
 /// Check if worktree is locked.
diff --git a/lib/src/blame.dart b/lib/src/blame.dart
index d01ab57..b1f02e3 100644
--- a/lib/src/blame.dart
+++ b/lib/src/blame.dart
@@ -2,10 +2,10 @@ import 'dart:collection';
 import 'dart:ffi';
 
 import 'package:equatable/equatable.dart';
+import 'package:ffi/ffi.dart';
 import 'package:libgit2dart/libgit2dart.dart';
 import 'package:libgit2dart/src/bindings/blame.dart' as bindings;
 import 'package:libgit2dart/src/bindings/libgit2_bindings.dart';
-import 'package:libgit2dart/src/extensions.dart';
 import 'package:meta/meta.dart';
 
 class Blame with IterableMixin<BlameHunk> {
@@ -174,7 +174,8 @@ class BlameHunk extends Equatable {
 
   /// Path to the file where this hunk originated, as of the commit specified by
   /// [originCommitOid].
-  String get originPath => _blameHunkPointer.ref.orig_path.toDartString();
+  String get originPath =>
+      _blameHunkPointer.ref.orig_path.cast<Utf8>().toDartString();
 
   @override
   String toString() {
diff --git a/lib/src/config.dart b/lib/src/config.dart
index 7ccce28..2a63645 100644
--- a/lib/src/config.dart
+++ b/lib/src/config.dart
@@ -7,7 +7,6 @@ import 'package:ffi/ffi.dart';
 import 'package:libgit2dart/libgit2dart.dart';
 import 'package:libgit2dart/src/bindings/config.dart' as bindings;
 import 'package:libgit2dart/src/bindings/libgit2_bindings.dart';
-import 'package:libgit2dart/src/extensions.dart';
 import 'package:libgit2dart/src/util.dart';
 import 'package:meta/meta.dart';
 
@@ -99,8 +98,8 @@ class Config with IterableMixin<ConfigEntry> {
       configPointer: _configPointer,
       variable: variable,
     );
-    final name = entryPointer.ref.name.toDartString();
-    final value = entryPointer.ref.value.toDartString();
+    final name = entryPointer.ref.name.cast<Utf8>().toDartString();
+    final value = entryPointer.ref.value.cast<Utf8>().toDartString();
     final includeDepth = entryPointer.ref.include_depth;
     final level = GitConfigLevel.values.firstWhere(
       (e) => entryPointer.ref.level == e.value,
@@ -265,8 +264,8 @@ class _ConfigIterator implements Iterator<ConfigEntry> {
     } else {
       error = libgit2.git_config_next(entry, _iteratorPointer);
       if (error != -31) {
-        final name = entry.value.ref.name.toDartString();
-        final value = entry.value.ref.value.toDartString();
+        final name = entry.value.ref.name.cast<Utf8>().toDartString();
+        final value = entry.value.ref.value.cast<Utf8>().toDartString();
         final includeDepth = entry.value.ref.include_depth;
         final level = GitConfigLevel.values.firstWhere(
           (e) => entry.value.ref.level == e.value,
diff --git a/lib/src/diff.dart b/lib/src/diff.dart
index 9ca2605..d8c6c9e 100644
--- a/lib/src/diff.dart
+++ b/lib/src/diff.dart
@@ -1,10 +1,10 @@
 import 'dart:ffi';
 
 import 'package:equatable/equatable.dart';
+import 'package:ffi/ffi.dart';
 import 'package:libgit2dart/libgit2dart.dart';
 import 'package:libgit2dart/src/bindings/diff.dart' as bindings;
 import 'package:libgit2dart/src/bindings/libgit2_bindings.dart';
-import 'package:libgit2dart/src/extensions.dart';
 import 'package:libgit2dart/src/util.dart';
 import 'package:meta/meta.dart';
 
@@ -546,7 +546,7 @@ class DiffFile extends Equatable {
   Oid get oid => Oid.fromRaw(_diffFile.id);
 
   /// Path to the entry relative to the working directory of the repository.
-  String get path => _diffFile.path.toDartString();
+  String get path => _diffFile.path.cast<Utf8>().toDartString();
 
   /// Size of the entry in bytes.
   int get size => _diffFile.size;
diff --git a/lib/src/error.dart b/lib/src/error.dart
index 97eec9b..83cac80 100644
--- a/lib/src/error.dart
+++ b/lib/src/error.dart
@@ -1,8 +1,8 @@
 // coverage:ignore-file
 
 import 'dart:ffi';
+import 'package:ffi/ffi.dart';
 import 'package:libgit2dart/src/bindings/libgit2_bindings.dart';
-import 'package:libgit2dart/src/extensions.dart';
 
 /// Details of the last error that occurred.
 class LibGit2Error {
@@ -11,5 +11,7 @@ class LibGit2Error {
   final Pointer<git_error> _errorPointer;
 
   @override
-  String toString() => _errorPointer.ref.message.toDartString();
+  String toString() {
+    return _errorPointer.ref.message.cast<Utf8>().toDartString();
+  }
 }
diff --git a/lib/src/extensions.dart b/lib/src/extensions.dart
deleted file mode 100644
index 9f12e06..0000000
--- a/lib/src/extensions.dart
+++ /dev/null
@@ -1,36 +0,0 @@
-// coverage:ignore-file
-
-import 'dart:ffi';
-
-import 'package:ffi/ffi.dart';
-import 'package:libgit2dart/src/bindings/libgit2_bindings.dart';
-
-extension IsValidSHA on String {
-  bool isValidSHA() {
-    final hexRegExp = RegExp(r'^[0-9a-fA-F]+$');
-    return hexRegExp.hasMatch(this) &&
-        (GIT_OID_MINPREFIXLEN <= length && GIT_OID_HEXSZ >= length);
-  }
-}
-
-extension ToChar on String {
-  /// Creates a zero-terminated [Utf8] code-unit array from this String,
-  /// casts it to the C `char` type and returns allocated pointer to result.
-  Pointer<Char> toChar() => toNativeUtf8().cast<Char>();
-}
-
-extension ToDartString on Pointer<Char> {
-  /// Converts this UTF-8 encoded string to a Dart string.
-  ///
-  /// Decodes the UTF-8 code units of this zero-terminated byte array as
-  /// Unicode code points and creates a Dart string containing those code
-  /// points.
-  ///
-  /// If [length] is provided, zero-termination is ignored and the result can
-  /// contain NUL characters.
-  ///
-  /// If [length] is not provided, the returned string is the string up til but
-  /// not including the first NUL character.
-  String toDartString({int? length}) =>
-      cast<Utf8>().toDartString(length: length);
-}
diff --git a/lib/src/index.dart b/lib/src/index.dart
index 63edaad..d74eaf3 100644
--- a/lib/src/index.dart
+++ b/lib/src/index.dart
@@ -2,10 +2,10 @@ import 'dart:collection';
 import 'dart:ffi';
 
 import 'package:equatable/equatable.dart';
+import 'package:ffi/ffi.dart';
 import 'package:libgit2dart/libgit2dart.dart';
 import 'package:libgit2dart/src/bindings/index.dart' as bindings;
 import 'package:libgit2dart/src/bindings/libgit2_bindings.dart';
-import 'package:libgit2dart/src/extensions.dart';
 import 'package:meta/meta.dart';
 
 class Index with IterableMixin<IndexEntry> {
@@ -345,9 +345,10 @@ class IndexEntry extends Equatable {
   set oid(Oid oid) => _indexEntryPointer.ref.id = oid.pointer.ref;
 
   /// Path of the index entry.
-  String get path => _indexEntryPointer.ref.path.toDartString();
+  String get path => _indexEntryPointer.ref.path.cast<Utf8>().toDartString();
 
-  set path(String path) => _indexEntryPointer.ref.path = path.toChar();
+  set path(String path) =>
+      _indexEntryPointer.ref.path = path.toNativeUtf8().cast<Char>();
 
   /// UNIX file attributes of a index entry.
   GitFilemode get mode {
diff --git a/lib/src/libgit2.dart b/lib/src/libgit2.dart
index 44245fa..29ab98d 100644
--- a/lib/src/libgit2.dart
+++ b/lib/src/libgit2.dart
@@ -3,7 +3,6 @@ import 'dart:ffi';
 import 'package:ffi/ffi.dart';
 import 'package:libgit2dart/libgit2dart.dart';
 import 'package:libgit2dart/src/bindings/libgit2_bindings.dart';
-import 'package:libgit2dart/src/extensions.dart';
 import 'package:libgit2dart/src/util.dart';
 
 class Libgit2 {
@@ -103,7 +102,7 @@ class Libgit2 {
 
     final out = calloc<git_buf>();
     libgit2Opts.git_libgit2_opts_get_search_path(level.value, out);
-    final result = out.ref.ptr.toDartString(length: out.ref.size);
+    final result = out.ref.ptr.cast<Utf8>().toDartString(length: out.ref.size);
 
     libgit2.git_buf_dispose(out);
     calloc.free(out);
@@ -130,7 +129,7 @@ class Libgit2 {
   }) {
     libgit2.git_libgit2_init();
 
-    final pathC = path?.toChar() ?? nullptr;
+    final pathC = path?.toNativeUtf8().cast<Char>() ?? nullptr;
     libgit2Opts.git_libgit2_opts_set_search_path(level.value, pathC);
     calloc.free(pathC);
   }
@@ -202,7 +201,7 @@ class Libgit2 {
 
     final out = calloc<git_buf>();
     libgit2Opts.git_libgit2_opts_get_template_path(out);
-    final result = out.ref.ptr.toDartString(length: out.ref.size);
+    final result = out.ref.ptr.cast<Utf8>().toDartString(length: out.ref.size);
 
     libgit2.git_buf_dispose(out);
     calloc.free(out);
@@ -213,7 +212,7 @@ class Libgit2 {
   static set templatePath(String path) {
     libgit2.git_libgit2_init();
 
-    final pathC = path.toChar();
+    final pathC = path.toNativeUtf8().cast<Char>();
     libgit2Opts.git_libgit2_opts_set_template_path(pathC);
 
     calloc.free(pathC);
@@ -235,8 +234,8 @@ class Libgit2 {
     } else {
       libgit2.git_libgit2_init();
 
-      final fileC = file?.toChar() ?? nullptr;
-      final pathC = path?.toChar() ?? nullptr;
+      final fileC = file?.toNativeUtf8().cast<Char>() ?? nullptr;
+      final pathC = path?.toNativeUtf8().cast<Char>() ?? nullptr;
 
       libgit2Opts.git_libgit2_opts_set_ssl_cert_locations(fileC, pathC);
 
@@ -254,7 +253,7 @@ class Libgit2 {
 
     final out = calloc<git_buf>();
     libgit2Opts.git_libgit2_opts_get_user_agent(out);
-    final result = out.ref.ptr.toDartString(length: out.ref.size);
+    final result = out.ref.ptr.cast<Utf8>().toDartString(length: out.ref.size);
 
     libgit2.git_buf_dispose(out);
     calloc.free(out);
@@ -265,7 +264,7 @@ class Libgit2 {
   static set userAgent(String userAgent) {
     libgit2.git_libgit2_init();
 
-    final userAgentC = userAgent.toChar();
+    final userAgentC = userAgent.toNativeUtf8().cast<Char>();
     libgit2Opts.git_libgit2_opts_set_user_agent(userAgentC);
 
     calloc.free(userAgentC);
@@ -484,7 +483,7 @@ class Libgit2 {
 
     final result = <String>[
       for (var i = 0; i < array.ref.count; i++)
-        array.ref.strings.elementAt(i).value.toDartString()
+        array.ref.strings.elementAt(i).value.cast<Utf8>().toDartString()
     ];
 
     calloc.free(array);
@@ -497,7 +496,7 @@ class Libgit2 {
 
     final array = calloc<Pointer<Char>>(extensions.length);
     for (var i = 0; i < extensions.length; i++) {
-      array[i] = extensions[i].toChar();
+      array[i] = extensions[i].toNativeUtf8().cast<Char>();
     }
 
     libgit2Opts.git_libgit2_opts_set_extensions(array, extensions.length);
diff --git a/lib/src/note.dart b/lib/src/note.dart
index 1dd874b..6ba83c2 100644
--- a/lib/src/note.dart
+++ b/lib/src/note.dart
@@ -114,17 +114,9 @@ class Note extends Equatable {
 
   /// Returns list of notes for [repo]sitory.
   ///
-  /// [notesRef] is the canonical name of the reference to use. Defaults to "refs/notes/commits".
-  ///
   /// Throws a [LibGit2Error] if error occured.
-  static List<Note> list(
-    Repository repo, {
-    String notesRef = 'refs/notes/commits',
-  }) {
-    final notesPointers = bindings.list(
-      repoPointer: repo.pointer,
-      notesRef: notesRef,
-    );
+  static List<Note> list(Repository repo) {
+    final notesPointers = bindings.list(repo.pointer);
     return notesPointers
         .map(
           (e) => Note(
diff --git a/lib/src/oid.dart b/lib/src/oid.dart
index ceca4b1..74a794c 100644
--- a/lib/src/oid.dart
+++ b/lib/src/oid.dart
@@ -5,7 +5,7 @@ import 'package:libgit2dart/libgit2dart.dart';
 import 'package:libgit2dart/src/bindings/libgit2_bindings.dart';
 import 'package:libgit2dart/src/bindings/odb.dart' as odb_bindings;
 import 'package:libgit2dart/src/bindings/oid.dart' as bindings;
-import 'package:libgit2dart/src/extensions.dart';
+import 'package:libgit2dart/src/util.dart';
 import 'package:meta/meta.dart';
 
 @immutable
@@ -24,7 +24,7 @@ class Oid extends Equatable {
   ///
   /// Throws a [LibGit2Error] if error occured.
   Oid.fromSHA({required Repository repo, required String sha}) {
-    if (sha.isValidSHA()) {
+    if (isValidShaHex(sha)) {
       if (sha.length == 40) {
         _oidPointer = bindings.fromSHA(sha);
       } else {
diff --git a/lib/src/signature.dart b/lib/src/signature.dart
index c533191..fb410ed 100644
--- a/lib/src/signature.dart
+++ b/lib/src/signature.dart
@@ -1,10 +1,9 @@
 import 'dart:ffi';
-
 import 'package:equatable/equatable.dart';
+import 'package:ffi/ffi.dart';
 import 'package:libgit2dart/libgit2dart.dart';
 import 'package:libgit2dart/src/bindings/libgit2_bindings.dart';
 import 'package:libgit2dart/src/bindings/signature.dart' as bindings;
-import 'package:libgit2dart/src/extensions.dart';
 import 'package:libgit2dart/src/util.dart';
 import 'package:meta/meta.dart';
 
@@ -65,10 +64,10 @@ class Signature extends Equatable {
   Pointer<git_signature> get pointer => _signaturePointer;
 
   /// Full name of the author.
-  String get name => _signaturePointer.ref.name.toDartString();
+  String get name => _signaturePointer.ref.name.cast<Utf8>().toDartString();
 
   /// Email of the author.
-  String get email => _signaturePointer.ref.email.toDartString();
+  String get email => _signaturePointer.ref.email.cast<Utf8>().toDartString();
 
   /// Time in seconds from epoch.
   int get time => _signaturePointer.ref.when.time;
diff --git a/lib/src/util.dart b/lib/src/util.dart
index 11ae887..91b562a 100644
--- a/lib/src/util.dart
+++ b/lib/src/util.dart
@@ -88,3 +88,9 @@ DynamicLibrary loadLibrary(String name) {
 
 final libgit2 = Libgit2(loadLibrary(getLibName()));
 final libgit2Opts = Libgit2Opts(loadLibrary(getLibName()));
+
+bool isValidShaHex(String str) {
+  final hexRegExp = RegExp(r'^[0-9a-fA-F]+$');
+  return hexRegExp.hasMatch(str) &&
+      (GIT_OID_MINPREFIXLEN <= str.length && GIT_OID_HEXSZ >= str.length);
+}