@Override
  public void stop() {
    this.executor.shutdown();
    this.rsReportExecutor.shutdown();
  }
Set RSReport requests handlers count when masters use MasterFifoRpcScheduler. The default value
is half of "hbase.regionserver.handler.count" value, but at least 1. The other handlers count
is "hbase.regionserver.handler.count" value minus RSReport handlers count, but at least 1 too.
hbase-server/src/main/java/org/apache/hadoop/hbase/ipc/MasterFifoRpcScheduler.java