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