@Override
  public boolean equals(Object o) {
    if (this == o) {
      return true;
    }
    if (o == null || getClass() != o.getClass()) {
      return false;
    }
    MetricsHeader that = (MetricsHeader) o;
    return time == that.time && resetTime == that.resetTime && Objects.equals(jobName, that.jobName) && Objects.equals(
        jobId, that.jobId) && Objects.equals(containerName, that.containerName) && Objects.equals(
        execEnvironmentContainerId, that.execEnvironmentContainerId) && Objects.equals(samzaEpochId,
        that.samzaEpochId) && Objects.equals(source, that.source) && Objects.equals(version, that.version)
        && Objects.equals(samzaVersion, that.samzaVersion) && Objects.equals(host, that.host);
  }
Epoch id for the application, which is consistent across all components of a single deployment attempt.
This may be empty, since this field was added to this class after the initial version.
samza-core/src/main/java/org/apache/samza/metrics/reporter/MetricsHeader.java