childManager property Null safety
protected">@protected
The delegate that manages the children of this object.
Rather than having a concrete list of children, a RenderSliverMultiBoxAdaptor uses a RenderSliverBoxChildManager to create children during layout in order to fill the SliverConstraints.remainingPaintExtent.
Implementation
@protected
RenderSliverBoxChildManager get childManager => _childManager;