toOptionsJSON method 
    
    
    
  Implementation
  @override
void toOptionsJSON(StringBuffer buffer) {
  super.toOptionsJSON(buffer);
  if (enabled != null) {
    buffer.writeAll(['"enabled":', enabled, ','], '');
  }
  if (focusBorder != null) {
    buffer.writeAll(['"focusBorder":', focusBorder?.toJSON(), ','], '');
  }
  if (order != null) {
    buffer.write('"order":[');
    for (var item in order!) {
      buffer.writeAll([jsonEncode(item), ','], '');
    }
    buffer.write('],');
  }
  if (seriesNavigation != null) {
    buffer.writeAll(
        ['"seriesNavigation":', seriesNavigation?.toJSON(), ','], '');
  }
  if (wrapAround != null) {
    buffer.writeAll(['"wrapAround":', wrapAround, ','], '');
  }
}