toOptionsJSON method
Implementation
@override
void toOptionsJSON(StringBuffer buffer) {
  super.toOptionsJSON(buffer);
  if (color != null) {
    buffer.writeAll(['"color":', jsonEncode(color), ','], '');
  }
}@override
void toOptionsJSON(StringBuffer buffer) {
  super.toOptionsJSON(buffer);
  if (color != null) {
    buffer.writeAll(['"color":', jsonEncode(color), ','], '');
  }
}