setData method
Implementation
@override
void setData(int index, ChartSegment segment) {
  super.setData(index, segment);
  segment as ScatterSegment<T, D>
    ..series = this
    ..xValue = xValues[index]
    ..yValue = yValues[index]
    ..width = markerSettings.width
    ..height = markerSettings.height
    ..shape = markerSettings.shape
    ..isEmpty = isEmpty(index);
}