anchor.diff:      });
     }
   
  +  /// The build context for the subtree containing the primary content of this route.
     BuildContext get subtreeContext => _subtreeKey.currentContext;
   
   
  
positive.code:     }
    }
  
    bool canTransitionTo(TransitionRoute nextRoute) => true;
    bool canTransitionFrom(TransitionRoute nextRoute) => true;
  
    void finished() {
  
negative.code:   Future<T> get completed => _transitionCompleter?.future;
    final Completer<T> _transitionCompleter;
  
    /// The duration the transition lasts.
    Duration get transitionDuration;
  
    /// Whether the route obscures previous routes when the transition is complete.
    ///
    /// When an opaque route's entrance transition is complete, the routes behind
    /// the opaque route will not be built to save resources.
    bool get opaque;
  
    /// The animation that drives the route's transition and the previous route's
    /// forward transition.
    Animation<double> get animation => _animation;
    Animation<double> _animation;
    AnimationController _controller;
  