code: protected function getReaderFactory()
      {
          if (!$this->readerFactory) {
              $this->readerFactory = new ReaderFactory([
                  new Json(),
                  new Xml(),
              ]);
          }
          return $this->readerFactory;
      }
docs: Get the reader factory.
  
  If none is set, then create one, set it and return it. By default it
  will only be able to read Xml and Json.
  
  @return ReaderFactory