Convert a BitmapImage to byte array in UWP

How can I convert a BitmapImage object to byte array in UWP ? in .Net it is easy to achieve, even in previous WinRT versions, looked all over the internet but without success, one of the solutions was to use a WriteableBitmap like mentioned in this answer, but in the current version of UWP, constructing a WriteableBitmap out of a BitmapImage isn't possible, any work around ?