A transactional queue that can only be enqueued.
The maximum capacity of the queue.
Checks whether the queue is shut down.
Offers a value to the queue, returning whether the value was offered to the queue.
Offers all of the specified values to the queue, returning whether they were offered to the queue.
Shuts down the queue.
The current number of values in the queue.
Waits for the hub to be shut down.
Checks if the queue is empty.
Checks if the queue is at capacity.