code: public void logJobPriority(JobID jobid, JobPriority priority) {
      if (disableHistory) {
        return;
      }
  
      if (null != writers) {
        log(writers, RecordTypes.Job,
            new Keys[] {Keys.JOBID, Keys.JOB_PRIORITY},
            new String[] {jobId.toString(), priority.toString()});
      }
    }
docs: Log job's priority.
  @param priority Jobs priority