public MainViewModel(AuthorizationService authorizationService)
        {
            _authorizationService = authorizationService;
            _heartbeatService     = new HeartbeatService(_authorizationService);
            ClosingCommand        = new AsyncCommand <object>(async(unused, token) => await _heartbeatService.Stop());
            ViewUpdatedCommand    = new RelayCommand(o =>
            {
                OnPropertyChanged("CurrentContent");
            }, o => true);


            CreateNavigation();
        }