createRenderer method
to create a Step area series renderer
Implementation
StepAreaSeriesRenderer createRenderer(ChartSeries<T, D> series) {
StepAreaSeriesRenderer stepAreaRenderer;
if (onCreateRenderer != null) {
stepAreaRenderer = onCreateRenderer!(series) as StepAreaSeriesRenderer;
// ignore: unnecessary_null_comparison
assert(stepAreaRenderer != null,
'This onCreateRenderer callback function should return value as extends from ChartSeriesRenderer class and should not be return value as null');
return stepAreaRenderer;
}
return StepAreaSeriesRenderer();
}