How can I save a image from stream to my Android device's folder in Xamarin.Forms?

I'm capturing screenshot from a XAML element using the ImageFromXamarinUI plugin and it returns me a Stream.

  public ICommand CaptureCommand => new Command<VisualElement>(OnCapture);

    async void OnCapture(VisualElement element)
    {
        var stream = await element.CaptureImageAsync();
    }

How can I save the image I have captured using the Stream I got to a folder on my Android device as a png file?