code: @Override
      public Iterator<String> registeredKeys() {
          Iterator<HandlerPath> paths = handlerKeys.iterator();
          List<String> registeredKeys = new ArrayList<String>(handlerKeys.size());
          while (paths.hasNext()) {
              HandlerPath path = paths.next();
              if (!path.isHidden()) {
                  registeredKeys.add(path.getRegisteredPath());
              }
          }
  
          return registeredKeys.iterator();
      }
docs: Return our registered keys.