anchor.diff:      this.floatingActionButton,
       this.navigationTypeResolver,
     })  : assert(currentIndex != null),
  -        assert(destinations != null);
  +        assert(destinations != null),
  +        super(key: key);
   
  -  @override
  -  _AdaptiveNavigationScaffoldState createState() =>
  -      _AdaptiveNavigationScaffoldState();
  -}
  -
  -class _AdaptiveNavigationScaffoldState
  -    extends State<AdaptiveNavigationScaffold> {
     NavigationType _defaultNavigationTypeResolver(BuildContext context) {
       if (_isLargeScreen(context)) {
         return NavigationType.drawer;
  
positive.code:   final FloatingActionButton floatingActionButton;
    final NavigationTypeResolver navigationTypeResolver;
  
    AdaptiveNavigationScaffold({
      this.title,
      this.body,
      @required this.currentIndex,
  
negative.code: /// A widget that adapts to the current display size, displaying a [Drawer],
  /// [NavigationRail], or [BottomNavigationBar]. Navigation destinations are
  /// defined in the [destinations] parameter.
  class AdaptiveNavigationScaffold extends StatelessWidget {
    final Widget title;
    final Widget body;
    final int currentIndex;
  