anchor.diff:    }
   
     void push(RouteBase route) {
  -    HistoryEntry historyEntry = new HistoryEntry(route);
  +    HistoryEntry historyEntry = new HistoryEntry(route: route, key: _lastKey++);
       history.insert(historyIndex + 1, historyEntry);
       historyIndex++;
     }
  
positive.code:       }
        if (content == null)
          continue;
        String key = historyEntry.route.key;
        Transition transition = new Transition(
          key: key,
          content: content,
          direction: (i <= state.historyIndex) ? TransitionDirection.forward : TransitionDirection.reverse,
          interactive: (i == state.historyIndex),
  
negative.code:       if (route.name != null)
          namedRoutes[route.name] = route;
      }
      history.add(new HistoryEntry(route: routes[0], key: _lastKey++));
    }
  
    List<HistoryEntry> history = new List<HistoryEntry>();
    int historyIndex = 0;
    int _lastKey = 0;
    Map<String, RouteBase> namedRoutes = new Map<String, RouteBase>();
  
    RouteBase get currentRoute => history[historyIndex].route;
  