anchor.diff:    userHasExited(HttpRequest req) {
       _stack.add("User has exited");
       _writeResponse(req);
  +    _stack.add("(${new DateTime.now().difference(start).inMilliseconds}ms) User has exited");
     }
   
     userHasEntered(HttpRequest req) {
       _stack.add("User has entered");
       _writeResponse(req);
  +    _stack.add("(${new DateTime.now().difference(start).inMilliseconds}ms) User has entered");
     }
   
     goHandler(HttpRequest req) {
       int floor = int.parse(req.uri.queryParameters['floorToGo']);
       _elevator.goTo(floor);
  -    _stack.add('Go to floor ${floor} received / Elevator: ${_elevator}'); 
       _writeResponse(req);
  +    _stack.add('(${new DateTime.now().difference(start).inMilliseconds}ms) Go to floor ${floor} received / Elevator: ${_elevator}'); 
     }
     
     resetHandler(HttpRequest req) {
       _elevator.reset();
  -    _stack.add('Reset received: ${req.uri.query}');
       _stack.addStackShot(5);
       _writeResponse(req);
  +    _stack.add('(${new DateTime.now().difference(start).inMilliseconds}ms) Reset received: ${req.uri.query}');
     }
   
     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
  
positive.code:     req.response..writeln(response)..close();
    }
    
    ///
    /// A new incoming call
    /// 
  
negative.code:   
  }
  
  
  
  /**
  