The RadioButton is also a very usefull control for mobile developers, but currently its not available from scratch.
So I implemented my own radio button which can be used for Android and UWP (iOS will coming soon).
For the implementation i use the platform specific ViewRenderer and a Xamarin.Forms control for showing the control.
This is the result:


The source code can be found on:
https://github.com/WaiseFass/Xamarin.Playground/tree/master/RadioButton