@Override
  public boolean isExpired(NetworkRequest request) {
    if (request.equals(EmptyRequest.getInstance())) {
      // This is an internal generated request used to signal shutdown. Don't consider it as expired.
      return false;
    }
    return time.milliseconds() - request.getStartTimeInMs() > timeout;
  }
@param timeout for the requests waiting in the incoming request queue.
@param time system {@link Time}
@param capacity capacity of the queue holding incoming requests.
ambry-network/src/main/java/com/github/ambry/network/FifoNetworkRequestQueue.java