Dart APIunself_componentConditionalParentWidgetconditionalBuilder conditionalBuilder property Null safety Widget Function(Widget child) conditionalBuilder final Implementation final Widget Function(Widget child) conditionalBuilder; unself_component unself_component ConditionalParentWidget conditionalBuilder property ConditionalParentWidget class Constructors ConditionalParentWidget Properties child condition conditionalBuilder hashCode key runtimeType Methods build createElement debugDescribeChildren debugFillProperties noSuchMethod toDiagnosticsNode toString toStringDeep toStringShallow toStringShort Operators operator ==