code: protected function renderLink(ItemInterface $item, array $options = array())
      {
          if ($item->getUri() && (!$item->isCurrent() || $options['currentAsLink'])) {
              $text = $this->renderLinkElement($item, $options);
          } else {
              $text = $this->renderSpanElement($item, $options);
          }
  
          return $this->format($text, 'link', $item->getLevel(), $options);
      }
docs: Renders the link in a a tag with link attributes or
  the label in a span tag with label attributes
  
  Tests if item has a an uri and if not tests if it's
  the current item and if the text has to be rendered
  as a link or not.
  
  @param ItemInterface $item    The item to render the link or label for
  @param array         $options The options to render the item
  
  @return string