private JobModelMonitors jobModelMonitors(JobModel jobModel) {
    StreamPartitionCountMonitor streamPartitionCountMonitor =
        this.streamPartitionCountMonitorFactory.build(jobModel.getConfig(),
          streamsChanged -> this.jobRestartSignal.restartJob());
    Optional<StreamRegexMonitor> streamRegexMonitor =
        this.streamRegexMonitorFactory.build(jobModel, jobModel.getConfig(),
          (initialInputSet, newInputStreams, regexesMonitored) -> this.jobRestartSignal.restartJob());
    return new JobModelMonitors(streamPartitionCountMonitor, streamRegexMonitor.orElse(null));
  }
Keeps track of if the job coordinator has completed all preparation for running the job, including
publishing a new job model and starting the job model monitors.
samza-core/src/main/java/org/apache/samza/coordinator/staticresource/StaticResourceJobCoordinator.java