@VisibleForTesting
    Gauge<Integer> getJobModelChangedAcrossApplicationAttempt() {
      return jobModelChangedAcrossApplicationAttempt;
    }
A container class to hold all the metrics related to {@link JobCoordinatorMetadataManager}.
samza-core/src/main/java/org/apache/samza/job/metadata/JobCoordinatorMetadataManager.java