docs: void registerEntry(ListIterator<PathElement> iterator, String elementValue, ConcreteNotificationHandlerRegistration.NotificationHandlerEntry entry) {
          final NotificationHandlerNodeRegistry newRegistry = new NotificationHandlerNodeRegistry(elementValue, this);
          final NotificationHandlerNodeRegistry existingRegistry = childRegistriesUpdater.putIfAbsent(this, elementValue, newRegistry);
  
          final NotificationHandlerNodeRegistry registry = existingRegistry != null ? existingRegistry : newRegistry;
          registry.registerEntry(iterator, entry);
      }