private void warmUpRegion(ServerName server, RegionInfo region) {
    FutureUtils.addListener(asyncClusterConnection.getRegionServerAdmin(server)
      .warmupRegion(RequestConverter.buildWarmupRegionRequest(region)), (r, e) -> {
        if (e != null) {
          LOG.warn("Failed to warm up region {} on server {}", region, server, e);
        }
      });
  }
Switch for the background CatalogJanitor thread. Used for testing. The thread will continue to
run. It will just be a noop if disabled.
@param b If false, the catalog janitor won't do anything.
hbase-server/src/main/java/org/apache/hadoop/hbase/master/HMaster.java