removeRenderObjectChild method
Remove the given child from renderObject.
The given child is guaranteed to have been inserted at the given slot
and have renderObject as its parent.
Implementation
@override
void removeRenderObjectChild(RenderObject child, slot) {
final RenderSliverStickyHeader renderObject =
this.renderObject as RenderSliverStickyHeader;
if (renderObject.header == child) renderObject.header = null;
if (renderObject.child == child) renderObject.child = null;
assert(renderObject == this.renderObject);
}