/*
* At this point, dequeuers see a NULL old_tail->next, which indicates
* that the queue is being appended to. The following store will append
* "node" to the queue from a dequeuer perspective.
*/
/*
* At this point, dequeuers see a NULL old_tail->next, which indicates
* that the queue is being appended to. The following store will append
* "node" to the queue from a dequeuer perspective.
*/