public static AsyncWriter createAsyncWriter(Configuration conf, FileSystem fs, Path path,
    boolean overwritable, EventLoopGroup eventLoopGroup, Class<? extends Channel> channelClass)
    throws IOException {
    return createAsyncWriter(conf, fs, path, overwritable, WALUtil.getWALBlockSize(conf, fs, path),
      eventLoopGroup, channelClass, StreamSlowMonitor.create(conf, path.getName()));
  }
Public because of AsyncFSWAL. Should be package-private
hbase-server/src/main/java/org/apache/hadoop/hbase/wal/AsyncFSWALProvider.java