func indexExists(ref ociReference) bool {
	_, err := os.Stat(ref.indexPath())
	if err == nil {
		return true
	}
	if os.IsNotExist(err) {
		return false
	}
	return true
}
func indexExists(ref ociReference) bool {
	_, err := os.Stat(ref.indexPath())
	if err == nil {
		return true
	}
	if os.IsNotExist(err) {
		return false
	}
	return true
}
// indexExists checks whether the index location specified in the OCI reference exists.
// The implementation is opinionated, since in case of unexpected errors false is returned