Dart APIunself_componentUnSliverAppBartitle title property Null safety Widget title final Implementation final Widget title; unself_component unself_component UnSliverAppBar title property UnSliverAppBar class Constructors UnSliverAppBar Properties description emoji hashCode implyLeading isCollapseCentered isImmersive key leading runtimeType title trailing Methods createElement createState debugDescribeChildren debugFillProperties noSuchMethod toDiagnosticsNode toString toStringDeep toStringShallow toStringShort Operators operator ==