private void closeWriter(WriterLength wl) throws IOException {
        if (wl.writer != null) {
          LOG.info(
            "Writer=" + wl.writer.getPath() + ((wl.written == 0) ? "" : ", wrote=" + wl.written));
          close(wl.writer);
          wl.writer = null;
        }
        wl.written = 0;
      }
ExtendedCell and ExtendedCellSerialization are InterfaceAudience.Private. We expose this config
for internal usage in jobs like WALPlayer which need to use features of ExtendedCell.
hbase-mapreduce/src/main/java/org/apache/hadoop/hbase/mapreduce/HFileOutputFormat2.java