public async Task StopSound()
        {
            if (RingtoneElement == null)
            {
                return;
            }

            await RingtoneElement.Dispatcher.RunAsync(CoreDispatcherPriority.Normal, () =>
            {
                RingtoneElement.Stop();
                RingtoneElement.Source = null;
            });
        }
        public async Task PlayRingtone(bool isIncomingCall)
        {
            if (RingtoneElement == null)
            {
                return;
            }
            var source = isIncomingCall
                ? "ms-appx:///Assets/Ringtones/IncomingCall.mp3"
                : "ms-appx:///Assets/Ringtones/OutgoingCall.mp3";

            await RingtoneElement.Dispatcher.RunAsync(CoreDispatcherPriority.Normal, () =>
            {
                RingtoneElement.Source = new Uri(source);
                RingtoneElement.Stop();
                RingtoneElement.Play();
            });
        }