append method
Appends to the end.
Implementation
@override
Future<int> append(Uint8List src, {int start = 0, int? end}) async {
_checkWritable();
final e = end ?? src.length;
RangeError.checkValidRange(start, e, src.length);
if (start == e) return 0;
return _serialize(() => _writeImpl(_manifest.logicalLength, src, start, e));
}