code: public static JobMetrics get(final JobState jobState, final MetricContext parentContext) {
      return (JobMetrics) GOBBLIN_METRICS_REGISTRY.getOrDefault(name(jobState), new Callable<GobblinMetrics>() {
        @Override
        public GobblinMetrics call() throws Exception {
          return new JobMetrics(jobState, parentContext);
        }
      });
    }
docs: Get a new {@link GobblinMetrics} instance for a given job.
  
  @param jobState the given {@link JobState} instance
  @param parentContext is the parent {@link MetricContext}
  @return a {@link JobMetrics} instance