code: @Override
    public RecordWriter getRecordWriter(TaskAttemptContext taskAttemptContext) throws IOException {
      Configuration conf = taskAttemptContext.getConfiguration();
      String extension = "." + conf.get(COMPACTION_OUTPUT_EXTENSION, "orc" );
  
      Path filename = getDefaultWorkFile(taskAttemptContext, extension);
      Writer writer = OrcFile.createWriter(filename,
          org.apache.orc.mapred.OrcOutputFormat.buildOptions(conf));
      return new OrcMapreduceRecordWriter(writer);
    }
docs: Required for extension since super method hard-coded file extension as ".orc". To keep flexibility
  of extension name, we made it configuration driven.
  @param taskAttemptContext The source of configuration that determines the file extension
  @return The {@link RecordWriter} that write out Orc object.
  @throws IOException