docs: @Subscribe
      public void handleIndexSetCreation(final IndexSetCreatedEvent event) {
          final String indexSetId = event.indexSet().id();
          // We are NOT using IndexSetRegistry#get(String) here because of this: https://github.com/Graylog2/graylog2-server/issues/4625
          final Optional<IndexSetConfig> optionalIndexSet = indexSetService.get(indexSetId);
  
          if (optionalIndexSet.isPresent()) {
              schedule(mongoIndexSetFactory.create(optionalIndexSet.get()));
          } else {
              LOG.warn("Couldn't find newly created index set <{}>", indexSetId);
          }
      }