public void startRegionCleaner() {
    synchronized (scheduleMonitor) {
      if (currentRegionMaintainerFuture == null) {
        /* Start the RegionCleaner service */
        currentRegionMaintainerFuture =
            ScheduledExecutorUtil.safelyScheduleAtFixedRate(
                regionMaintainer,
                this::maintainRegionReplicas,
                0,
                REGION_MAINTAINER_WORK_INTERVAL,
                TimeUnit.SECONDS);
        LOGGER.info("RegionCleaner is started successfully.");
      }
    }
  }
Called by {@link PartitionManager#regionMaintainer}.

<p>Periodically maintain the RegionReplicas to be created or deleted
iotdb-core/confignode/src/main/java/org/apache/iotdb/confignode/manager/partition/PartitionManager.java