TQueue implements a queue.
The typical queue operations are implemented, which include
{@link enqueue()}, {@link dequeue()} and {@link peek()}. In addition,
{@link contains()} can be used to check if an item is contained
in the queue. To obtain the number of the items in the queue,
check the {@link getCount Count} property.
Items in the queue may be traversed using foreach as follows,
foreach($queue as $item) ...