@Override
  public boolean dispatch(final CallRunner task) {
    String method = getCallMethod(task);
    if (rsReportExecutor != null && method != null && method.equals(REGION_SERVER_REPORT)) {
      return executeRpcCall(rsReportExecutor, rsReportQueueSize, task);
    } else {
      return executeRpcCall(executor, queueSize, task);
    }
  }
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