@Override
  public RecordWriter<ImmutableBytesWritable, Cell>
    getRecordWriter(final TaskAttemptContext context) throws IOException, InterruptedException {
    return createRecordWriter(context, this.getOutputCommitter(context));
  }
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