Dart APIunself_componentUnAppPagetrailing trailing property Null safety Widget? trailing final Implementation final Widget? trailing; unself_component unself_component UnAppPage trailing property UnAppPage class Constructors UnAppPage Properties description hashCode implyLeading isImmersive key leading name runtimeType slivers trailing Methods build createElement debugDescribeChildren debugFillProperties noSuchMethod toDiagnosticsNode toString toStringDeep toStringShallow toStringShort Operators operator ==