child property
Specifies a widget that can hold single child.
Widget build(BuildContext context) {
  return Scaffold(
    body: SfChartTheme(
      data: SfChartThemeData(
        brightness: Brightness.dark,
        backgroundColor: Colors.grey
      ),
      child: SfCartesianChart()
    ),
  );
}
Implementation
@override
final Widget child;