How to use a non-sliver widget in a CustomScrollView

I found a better way to use non-slivers inside a CustomScrollView, use SliverToBoxAdapter widget. Give your non-sliver widget as child of SliverToBoxAdapter widget and your work done.

return Scaffold(
  body: CustomScrollView(
    slivers: <Widget>[
      SliverToBoxAdapter(
        child: Stack(
          children: <Widget>[
            Container(
              height: 200,
              width: 200,
              color: Colors.green,
            ),
            Positioned(
              child: Container(color: Colors.yellow),
              top: 50,
              left: 50,
            )
          ],
        ),
      )
    ],
  ),
);

The best answer is not correct, it causes assertion padding == null. @blaneyneil wrote the right solution: use to SliverToBoxAdapter.