'package" flutter/src/widgets/framework.dart' : Failed assertion: 'child == _child': is not true

class Home extends StatelessWidget{

  @override
  Widget build(BuildContext context){
    return new MediaQuery(
      data: new MediaQueryData.fromWindow(ui.window),
      child: new SafeArea(
        child: new Material(
          child: new CustomScrollView(
            slivers: <Widget>[
              new SliverPersistentHeader(
                delegate: MyCustomAppBar(expandedHeight: 200),
                pinned: true,
              ),
              new SliverList(
                delegate: SliverChildBuilderDelegate(
                  (_,index) => ListTile(
                    title: Text(
                      "Index: $index",
                      textDirection: TextDirection.ltr,
                    ),
                  ),
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }
}

I am creating a custom scroll view but I am having the error and I can't understand from where it is generating?

I am using SliverPersistentHeaderDelegate class to create my custom appBar.