How to add an colored underline to a button on Xamarin.Forms Android

I am trying to add a colored underline to a Button on Xamarin.Forms. I made a custom renderer for iOS and got that working, but I can't seem to figure out a way to do it with a custom renderer on Android. The only thing i've found was adding a same color underline, but I want it to be a certain thickness and color. Anyone know how to handle this on Android?