public ShaMapLeaf InvalidatedPossiblyCopiedLeafForUpdating()
{
Debug.Assert(_matched);
if (_dirtied == null)
{
DirtyOrCopyInners();
}
var theLeaf = Leaf;
if (CopyLeafOnUpdate())
{
theLeaf = Leaf.Copy();
Top().SetLeaf(theLeaf);
}
theLeaf.Invalidate();
return(theLeaf);
}