func (q *PriorityQueue) Enqueue(val string, pr uint16) error {
	prefix := fmt.Sprintf("%s%05d", q.key, pr)
	_, err := newSequentialKV(q.client, prefix, val)
	return err
}
func (q *PriorityQueue) Enqueue(val string, pr uint16) error {
	prefix := fmt.Sprintf("%s%05d", q.key, pr)
	_, err := newSequentialKV(q.client, prefix, val)
	return err
}
// Enqueue puts a value into a queue with a given priority.