internal void Invalidate()
{
list = null;
next = null;
prev = null;
}
public void AddBefore(LinkedListNode <T> newNode)
{
Debug.Assert(list != null);
list.AddBefore(this, newNode);
}
public void Remove(LinkedListNode <T> node)
{
ValidateNode(node);
InternalRemoveNode(node);
}