How to convert MonoTouch.UIKit.UIImage to Xamarin.Forms.ImageSource?

I have a MonoTouch.UIKit.UIImage produced by the ZXing library on iOS that I want to display to the user on a Xamarin.Forms page. I've tried creating a Xamarin.Forms.Image control, but its Source property takes an Xamarin.Forms.ImageSource object.

How can I create an ImageSource object based on a UIImage object? Or is there a better way to do this?