code: public static Predicate<GHEventsSubscriber> isInterestedIn(final GHEvent event) {
          return new NullSafePredicate<GHEventsSubscriber>() {
              @Override
              protected boolean applyNullSafe(@Nonnull GHEventsSubscriber subscriber) {
                  return defaultIfNull(subscriber.events(), emptySet()).contains(event);
              }
          };
      }
docs: Predicate which returns true on apply if current subscriber is interested in event
  
  @param event should be one of {@link #events()} set to return true on apply
  
  @return predicate to match against {@link GHEventsSubscriber}