Dart APIunself_componentUnSheetanimationCurve animationCurve property Null safety Curve? animationCurve final Implementation final Curve? animationCurve; unself_component unself_component UnSheet<T> animationCurve 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 ==