@Override
  public boolean offer(E e, long timeout, TimeUnit unit) throws InterruptedException {
    return queue.offer(new DelayedElement<>(e, delayMs), timeout, unit);
  }
A blocking queue implementation for adding a constant delay. Uses a DelayQueue as a backing store
@param <E> type of elements
hbase-server/src/test/java/org/apache/hadoop/hbase/util/ConstantDelayQueue.java