Is possible to implement volume up|down in Google Actions V2

I'm working with MediaResponse to play media (play song) with Google Actions V2.

I did these features:

• Play audio

• Stop

• Pause

• Resume

• Play

• Next

• Previous

• Repeat

But I wonder that why MediaResponse did not support Volume intergration while I said

• Increase|Decrease Volume

• Volume Up|Down

Is there anyway for me to implement these features?

p/s :

- Spotify service can did it.

- I able to detect Intent with specify phrases : "Volume Up" ...

MediaResponse.js

    class MediaPlayerUtils {

    getMediaResponse(song) {
        // This object used to play Media on Google Home
        var mediaResponse = new MediaResponse();
        mediaResponse.mediaType = "AUDIO";

        var mediaObject = new MediaObject({
            url: ""
        });

        mediaObject.name = song.title;
        mediaObject.contentUrl = song.url;

        mediaResponse.mediaObjects = [];
        mediaResponse.mediaObjects.push(mediaObject);

        var Media = function (song, mediaResponse) {
            this.song = song;
            this.mediaResponse = mediaResponse;
        }

        // Media Response : Play audio
        return new Media(song, mediaResponse);
    }

    playSong(conv, song) {
        console.log("playSong() " + song.title + " --- " + song.url);

        var media = function (song, mediaResponse) {
            this.song = song;
            this.mediaResponse = mediaResponse;
        }
        media = this.getMediaResponse(song);

        // Media Response : Play audio
        conv.ask(new SimpleResponse(" ")); // Able to set song title before playing song in here
        conv.ask(media.mediaResponse);
        conv.ask(new Suggestions(
           'next',
           'back',
           'previous',
           'play',
           'pause',
           'resume',
           'stop',
           'volumeDown',
           'volumeUp'));
        conv.ask(new SimpleResponse(""));
    };

}