decode method
override
    Implementation
@override
(Uint8List, int) decode(int offset, Uint8List data) {
  final length = FunctionParamInt().decode(data.sublist(offset, offset + size_unit)).toInt();
  offset += size_unit;
  final value = data.sublist(offset, offset + length);
  offset += size_unit * ((length + size_unit - 1) ~/ size_unit);
  return (value, offset);
}