regions property Null safety
Define regions for each data. The values must be an array for each data and it should include an object that has start, end, style. If start is not set, the start will be the first data point. If end is not set, the end will be the last data point. Currently this option supports only line chart and dashed style. If this option specified, the line will be dashed only in the regions.
external dynamic /*JSMap of <String,dynamic>*/ get regions;
external set regions(dynamic /*JSMap of <String,dynamic>*/ v);