void AddPlayPauseAction(Notification.Builder builder)
        {
            LogHelper.Debug (Tag, "updatePlayPauseAction");
            string label;
            int icon;
            PendingIntent intent;

            if (playbackState.State == PlaybackStateCode.Playing) {
                label = service.GetString (Resource.String.label_pause);
                icon = Resource.Drawable.ic_pause_white_24dp;
                intent = pauseIntent;
            } else {
                label = service.GetString (Resource.String.label_play);
                icon = Resource.Drawable.ic_play_arrow_white_24dp;
                intent = playIntent;
            }
            builder.AddAction (new Notification.Action (icon, label, intent));
        }