fix #4 - use draggable scrollbar with sliver list

[Miolin]

change BoxScrollView to Widget

[jeprojects]

Can this be pushed to a new pub release?

[DenchikBY]

Have you tested this? Doesn't work for me inside CustomScrollView with sliver children. I'm trying to use it as a parent of SliverList.

A RenderViewport expected a child of type RenderSliver but received a child of type _RenderLayoutBuilder.

It works for me. Just regard a CustomScrollView with sliver children as a ListView in the example.

not working for me as well. i have customSCrollView and sliverList with sliverAppBar. could you please share your widget tree

Just looks like tihs↓ (myStickyBar is a sliverAppBar PS：You may need to change BoxScrollView to Widget following the commit above firstly.

But in your case wraps whole CustomScrollView, app bar too and scrollbar will be above it. Is it possible to wrap only SliverList?

[vauvenal5]

This PR is open since 2018... Is there any obvious issue with it?

[emvaized]

@Rizwan-Raza I get this error only when I pass ListView with shrinkWrap: true