behavior property
final
This defines the behavior and location of the snack bar.
Defines where a SnackBar should appear within a Scaffold and how its location should be adjusted when the scaffold also includes a FloatingActionButton or a BottomNavigationBar
If this property is null, then SnackBarThemeData.behavior of ThemeData.snackBarTheme is used. If that is null, then the default is SnackBarBehavior.fixed.
If this value is SnackBarBehavior.floating, the length of the bar is defined by either width or margin.
Implementation
final SnackBarBehavior? behavior;