createShaderDetails method
Implementation
@override
@nonVirtual
ChartShaderDetails createShaderDetails() {
  return ChartShaderDetails(
      Rect.fromCircle(center: center, radius: currentRadius), null, 'series');
}
@override
@nonVirtual
ChartShaderDetails createShaderDetails() {
  return ChartShaderDetails(
      Rect.fromCircle(center: center, radius: currentRadius), null, 'series');
}