@Override
  public CallQueueInfo getCallQueueInfo() {
    String queueName = "Fifo Queue";

    HashMap<String, Long> methodCount = new HashMap<>();
    HashMap<String, Long> methodSize = new HashMap<>();

    CallQueueInfo callQueueInfo = new CallQueueInfo();
    callQueueInfo.setCallMethodCount(queueName, methodCount);
    callQueueInfo.setCallMethodSize(queueName, methodSize);

    updateMethodCountAndSizeByQueue(executor.getQueue(), methodCount, methodSize);

    return callQueueInfo;
  }
A very simple {@code }RpcScheduler} that serves incoming requests in order. This can be used for
HMaster, where no prioritization is needed.
hbase-server/src/main/java/org/apache/hadoop/hbase/ipc/FifoRpcScheduler.java