static Pair<EventLoopGroup, Class<? extends Channel>> getEventLoopConfig(Configuration conf) {
    String name = conf.get(EVENT_LOOP_CONFIG);
    if (StringUtils.isBlank(name)) {
      // create new event loop group if config is empty
      return Pair.<EventLoopGroup, Class<? extends Channel>> newPair(
        new NioEventLoopGroup(0, new DefaultThreadFactory("AsyncFSWAL", true, Thread.MAX_PRIORITY)),
        NioSocketChannel.class);
    }
    return EVENT_LOOP_CONFIG_MAP.get(name);
  }
Set the EventLoopGroup and channel class for {@code AsyncFSWALProvider}.
hbase-server/src/main/java/org/apache/hadoop/hbase/wal/NettyAsyncFSWALConfigHelper.java