New returns a new priority queue where each priority has a buffer of prioQueueLimit.

High indicates the highest priority.

Low indicates the lowest priority.

Mid indicates the medium priority.

ErrQueueClosed indicates an attempt to read from a closed priority queue instance.

ErrUnknownPriority indicates an incorrect attempt to make a write with an unknown priority.

Queue is the priority queue.

Priority is the type that indicates the priority of different queues.