docs: @Override
  	public void grantLeadership(final UUID leaderSessionID) {
  		synchronized (lock) {
  			if (shutdown) {
  				log.info("JobManagerRunner already shutdown.");
  				return;
  			}
  
  			leadershipOperation = leadershipOperation.thenCompose(
  				(ignored) -> {
  					synchronized (lock) {
  						return verifyJobSchedulingStatusAndStartJobManager(leaderSessionID);
  					}
  				}