public void start() {
    if (isStarted) {
      log.info("Coordinator stream producer already started");
      return;
    }
    log.info("Starting coordinator stream producer.");
    systemProducer.start();
    systemAdmin.start();
    isStarted = true;
  }
Creates the coordinator stream, and starts the system producer.
samza-core/src/main/java/org/apache/samza/coordinator/stream/CoordinatorStreamSystemProducer.java