toOptionsJSON method
Implementation
@override
void toOptionsJSON(StringBuffer buffer) {
  super.toOptionsJSON(buffer);
  if (hover != null) {
    buffer.writeAll(['"hover":', hover?.toJSON(), ','], '');
  }
  if (inactive != null) {
    buffer.writeAll(['"inactive":', inactive?.toJSON(), ','], '');
  }
  if (normal != null) {
    buffer.writeAll(['"normal":', normal?.toJSON(), ','], '');
  }
  if (select != null) {
    buffer.writeAll(['"select":', select?.toJSON(), ','], '');
  }
}