anchor.diff:          if (e.target is AnchorElement) {
             AnchorElement anchor = e.target;
             if (anchor.host == window.location.host) {
  -            var fragment = (anchor.hash == '') ? '' : '${anchor.hash}'; 
  +            var fragment = (anchor.hash == '') ? '' : '${anchor.hash}';
               gotoPath("${anchor.pathname}$fragment", anchor.title);
               e.preventDefault();
             }
  
positive.code:       window.history.pushState(null, title, path);
      }
    }
    
    /**
     * Returns an [Event] handler suitable for use as a click handler on [:<a>:]
     * elements. The handler reverses [ur] with [args] and uses [window.pushState]
  
negative.code:  * and creating HTML event handlers that navigate to a URL.
   */
  class Router {
    final LinkedHashMap<UrlPattern, Handler> _handlers;
    final bool useFragment;
    bool _listen = false;
  
  