@Override
  public int getActiveWriteHandlerCount() {
    return activeWriteHandlerCount.get();
  }
RPC Executor that uses different queues for reads and writes. With the options to use different
queues/executors for gets and scans. Each handler has its own queue and there is no stealing.
hbase-server/src/main/java/org/apache/hadoop/hbase/ipc/RWQueueRpcExecutor.java