Dart APIunself_componentFloatScaffoldtrailing trailing property Null safety Widget? trailing final Implementation final Widget? trailing; unself_component unself_component FloatScaffold trailing property FloatScaffold class Constructors FloatScaffold Properties hashCode key leading middle runtimeType trailing Methods build createElement debugDescribeChildren debugFillProperties noSuchMethod toDiagnosticsNode toString toStringDeep toStringShallow toStringShort Operators operator ==