setData method
Implementation
@override
void setData(int index, ChartSegment segment) {
super.setData(index, segment);
segment as StackedAreaSegment<T, D>
..series = this
..currentSegmentIndex = 0
.._xValues = xValues
.._topValues = topValues
.._bottomValues = bottomValues
.._bottom = xAxis!.crossesAt;
}