I wanted to set radius for BulletSpan to make bullet larger then its default appearance. I found the solution on Android with link https://developer.android.com/reference/android/text/style/BulletSpan but same is not available in Xamarin Android BulletSpan.
Android Link explains about constructor which is not available in Xamarin Android part.
public BulletSpan (int gapWidth, int color, int bulletRadius)