code: public EventServiceLog createEventServiceLog(Class<? extends Subscriber> clazz) {
          if (LoggableSubscriber.class.isAssignableFrom(clazz)) {
              pm.currentTransaction().begin();
              final EventServiceLog log = new EventServiceLog();
              log.setSubscriberClass(clazz.getCanonicalName());
              log.setStarted(new Timestamp(new Date().getTime()));
              pm.makePersistent(log);
              pm.currentTransaction().commit();
              return getObjectById(EventServiceLog.class, log.getId());
          }
          return null;
      }
docs: Creates a new EventServiceLog. This method will automatically determine
  if the subscriber is an implementation of {@link LoggableSubscriber} and
  if so, will log the event. If not, then nothing will be logged and this
  method will return null.
  @param clazz the class of the subscriber task that handles the event
  @return a new EventServiceLog