@Override
          protected void initChannel(Channel ch) throws Exception {
            // we need to get the remote address of the channel so we can only move on after
            // channel connected. Leave an empty implementation here because netty does not allow
            // a null handler.
          }
Helper class for implementing {@link FanOutOneBlockAsyncDFSOutput}.
hbase-asyncfs/src/main/java/org/apache/hadoop/hbase/io/asyncfs/FanOutOneBlockAsyncDFSOutputHelper.java