docs: @Override
  	public void start() throws Exception {
  		synchronized (lock) {
  			if (jobExecutorService == null) {
  				// create the embedded runtime
  				jobExecutorServiceConfiguration = createConfiguration();
  
  				// start it up
  				jobExecutorService = createJobExecutorService(jobExecutorServiceConfiguration);
  			} else {
  				throw new IllegalStateException("The local executor was already started.");
  			}
  		}
  	}