Pushes the item into the queue. item must not be NULL.
In contrast to AsyncQueue.pushUnlocked, this function
pushes the new item ahead of the items already in the queue,
so that it will be the next one to be popped off the queue.
This function must be called while holding the queue's lock.
Pushes the item into the queue. item must not be NULL. In contrast to AsyncQueue.pushUnlocked, this function pushes the new item ahead of the items already in the queue, so that it will be the next one to be popped off the queue.
This function must be called while holding the queue's lock.