If shot button pressed too frequently image might loss on old iPhones

This is actually a feature request. Our UX stuff posted an issue about image lost on the old iPhone if press shot too quickly. So can we have something like ```func wrapperDidShotPress(_ imagePicker: ImagePickerController)``` and ```func wrapperDidShotFinish(_ imagePicker: ImagePickerController, image: UIImage)``` in delegate so we can do
```
func wrapperDidShotPress(_ imagePicker: ImagePickerController) {
imagePicker.shotButton.isEnabled = false
}

func wrapperDidShotFinish(_ imagePicker: ImagePickerController, image: UIImage) {
imagePicker.shotButton.isEnabled = true
}
```