Async gotcha in C#

MainPage.cs

async void AcquireFromCamera(object sender, RoutedEventArgs e)
{
    try
    {
        var imageStream = await _cameraCapture.Shoot();
        var dto = new Dto(){ImageStream = imageStream};
        dto.Id = Guid.NewGuid().ToString();
        var file = await _fileHndlr.CreateFileAsync(dto.Id);
        dto.ImageFilePath = file.Path;
        _fileOperator.StoreStream(dto.ImageStream, file);
        SaveNewDataItem(dto);
        var dataItem = dataSource.GetItem(dto.Id);
        StoreData(dataItem);
        Frame.Navigate(typeof(EditDataPage), dto.Id);
    }
    catch (Exception ex)
    {
        new MessageDialog(ex.Message).ShowAsync();
    }
}