How create round skbitmap

Hi, I need create round bitmap from SKBitmap

I get bitmap
public async Task GetPhoto()
{
try
{
Uri uri = new Uri();
WebRequest request =WebRequest.Create(uri);
WebResponse response = request.GetResponse();
Stream responseStream = response.GetResponseStream();
return SKBitmap.Decode(responseStream);
}
catch (Exception ex)
{

        }
        return new SKBitmap();
    }