Dart APIunself_componentUnSheetbarrierColor barrierColor property Null safety Color? barrierColor final Implementation final Color? barrierColor; unself_component unself_component UnSheet<T> barrierColor 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 ==