seriesPointMap property
Store a map of series drawn on the chart, mapped by series name.
LinkedHashMap is used to render the series on the canvas in the same order as the data was given to the chart.
Implementation
@protected
// ignore: prefer_collection_literals, https://github.com/dart-lang/linter/issues/1649
var seriesPointMap = LinkedHashMap<String, List<AnimatedPoint<D>>>();