NewPriorityQueue is the constructor for a priority queue.

ErrDisposed is returned when an operation is performed on a disposed queue.

ErrEmptyQueue is returned when an non-applicable queue operation was called due to the queue's empty item state.

ErrTimeout is returned when an applicable queue operation times out.

PriorityQueue is similar to queue except that it takes items that implement the Item interface and adds them to the queue in priority order.

Item is an item that can be added to the priority queue.