@Override
  public RecordWriter<NullWritable, WARCWritable> getRecordWriter(TaskAttemptContext context)
    throws IOException, InterruptedException {
    return new WARCWriter(context);
  }
Creates a new output file in WARC format, and returns a RecordWriter for writing to it.
hbase-it/src/test/java/org/apache/hadoop/hbase/test/util/warc/WARCOutputFormat.java