code: public void shutdown() throws Exception {
  		Throwable firstException = null;
  
  		try {
  			scheduledExecutorService.shutdownNow();
  		} catch (Throwable t) {
  			firstException = t;
  		}
  
  		libraryCacheManager.shutdown();
  		stackTraceSampleCoordinator.shutDown();
  		backPressureStatsTracker.shutDown();
  
  		if (firstException != null) {
  			ExceptionUtils.rethrowException(firstException, "Error while shutting down JobManager services");
  		}
  	}
docs: Shutdown the {@link JobMaster} services.
  
  <p>This method makes sure all services are closed or shut down, even when an exception occurred
  in the shutdown of one component. The first encountered exception is thrown, with successive
  exceptions added as suppressed exceptions.
  
  @throws Exception The first Exception encountered during shutdown.