anchor.diff:      int floor = int.parse(req.uri.queryParameters['atFloor']);
       Direction direction = req.uri.queryParameters['to'] == 'UP' ? Direction.UP : Direction.DOWN;
       _calls.add(new Call(floor, direction));
  -    _stack.add("Call at floor ${floor} direction ${direction}");
       _writeResponse(req);
  +    _stack.add("(${new DateTime.now().difference(start).inMilliseconds}ms) Call at floor ${floor} direction ${direction}");
     }
     
     lastResetHandler(HttpRequest req) {
  
positive.code:   userHasExited(HttpRequest req) {
      _stack.add("User has exited");
      _writeResponse(req);
    }
  
    userHasEntered(HttpRequest req) {
      _stack.add("User has entered");
      _writeResponse(req);
    }
  
    goHandler(HttpRequest req) {
      int floor = int.parse(req.uri.queryParameters['floorToGo']);
      _elevator.goTo(floor);
      _stack.add('Go to floor ${floor} received / Elevator: ${_elevator}'); 
      _writeResponse(req);
    }
    
    resetHandler(HttpRequest req) {
      _elevator.reset();
      _stack.add('Reset received: ${req.uri.query}');
      _stack.addStackShot(5);
      _writeResponse(req);
    }
  
    nextCommandHandler(HttpRequest req) {
      var start = new DateTime.now();
      // Verify if the elevator wants to accept new incoming call which are at the same floor as the elevator
      _calls.removeWhere(acceptCall(_elevator));
      // Get the command and apply it
  
negative.code:   
    HttpServer.bind('0.0.0.0', port).then(((HttpServer server) {
      var router = new Router(server)
      ..filter(matchAny(allUrls), building.log)
      ..serve(resetUrl, method: 'GET').listen(building.resetHandler)
      ..serve(nextCommandUrl, method: 'GET').listen(building.nextCommandHandler)
      ..serve(goUrl, method: 'GET').listen(building.goHandler)
  