public void start() {
    if (stopped) {
      LOG.info("starting");
      readWriteStore.init();
      fanOutStore.init();
      stopped = false;
    } else {
      LOG.warn("already started");
    }
  }
Perform startup operations. Method is idempotent.
samza-core/src/main/java/org/apache/samza/startpoint/StartpointManager.java