@Override
    public void operationComplete(ChannelFuture future) throws Exception {
      if (future.isSuccess()) {
        shuffleOutputsOK.incr();
      } else {
        shuffleOutputsFailed.incr();
      }
      shuffleConnections.decr();
    }
Should the shuffle use posix_fadvise calls to manage the OS cache during
sendfile
llap-server/src/java/org/apache/hadoop/hive/llap/shufflehandler/ShuffleHandler.java