func cropViewControllerDidTapDone(_ cropViewController: CropViewController) {
    // show activity indicator
}

func cropViewController(_ cropViewController: CropViewController, didCropToImage image: UIImage, withRect cropRect: CGRect, angle: Int) {
    // hide activity indicator
}

cropViewController.onDidTapDone = {
    // show activity indicator
}

cropViewController.onDidCropToRect = { image, cropRect, angle in
    // hide activity indicator
}