void Session_VolumeChanged(object sender, AudioSessionVolumeChangedEventArgs e)
        {
            r_IsMute = e.IsMute;
            r_Volume = e.Volume;

            OnPropertyChanged(nameof(IsMute));
            OnPropertyChanged(nameof(Volume));
        }
        void Session_VolumeChanged(object sender, AudioSessionVolumeChangedEventArgs e)
        {
            r_IsMute = e.IsMute;
            r_Volume = e.Volume;

            OnPropertyChanged(nameof(IsMute));
            OnPropertyChanged(nameof(Volume));
        }