Decode pgn file using a byte stream

lib/src/view/more/import_pgn_screen.dart

@@ -131,8 +131,9 @@ class _BodyState extends ConsumerState<_Body> {
       final result = await ref.read(pickPgnFileProvider)();
 
       if (result != null) {
-        final bytes = await result.files.single.readAsBytes();
-        final content = utf8.decode(bytes, allowMalformed: true);
+        final content = await const Utf8Decoder(
+          allowMalformed: true,
+        ).bind(result.files.single.readAsByteStream()).join();
         if (mounted) {
           ImportPgnScreen.handlePgnText(context, content);
         }

test/view/more/import_pgn_screen_test.dart

@@ -21,7 +21,7 @@ class _FakePlatformFile extends PlatformFile {
   final Uint8List _fileBytes;
 
   @override
-  Future<Uint8List> readAsBytes() async => _fileBytes;
+  Stream<Uint8List> readAsByteStream() => Stream.value(_fileBytes);
 }
 
 void _mockClipboard(String text) {