Dart APIunself_componentUnSheetshadow shadow property Null safety BoxShadow? shadow final Implementation final BoxShadow? shadow; unself_component unself_component UnSheet<T> shadow property UnSheet class Constructors UnSheet Properties animationCurve arguments backgroundColor barrierColor bounce child clipBehavior closeProgressThreshold duration elevation enableDrag expand hashCode isDismissible key name overlayStyle previousRouteAnimationCurve restorationId runtimeType secondAnimation settings shadow shape topRadius transitionBackgroundColor useRootNavigator Methods canUpdate createRoute noSuchMethod toString Operators operator ==