margin property Null safety
final
Empty space to surround the snack bar.
This property is only used when behavior is SnackBarBehavior.floating. It can not be used if width is specified.
If this property is null, then the default is
EdgeInsets.fromLTRB(15.0, 5.0, 15.0, 10.0).
Implementation
final EdgeInsetsGeometry? margin;