Add a onValueChange prop

Could it be possible to have a `onValueChange` prop which would be called at the same time as `setBallonText` but with a non formatted value ? Such as https://www.npmjs.com/package/@react-native-community/slider

 I am currently using `setBallonText` with values from 0 to 100 to make a volume slider, and it works quite good, but a props specifically for this would be cool