public async void Handle(CounterIncrementedWithAckEvent message)
        {
            var viewModel = _modelManager.Get <CounterDisplayPageViewModel>();

            if (null == viewModel)
            {
                viewModel = new CounterDisplayPageViewModel();
            }

            viewModel.AcknowledgedCounter++;

            _modelManager.Put(viewModel);

            await _bus.Acknowledge(message);
        }