method rectangle

Source

Future<bool> rectangle(int x, int y, int width, int height, int color,
        {bool fill: false, int radius}) =>
    proto.write(
        (fill ? 10 : 9) + ((radius != null) ? 2 : 0),
        _s2b(x)
          ..addAll(_s2b(y))
          ..addAll(_s2b(width))
          ..addAll(_s2b(height))
          ..addAll(radius != null ? _s2b(radius) : const <int>[])
          ..addAll(_s2b(color)));