addTrack method
      
RTCRtpSender
addTrack(
    
    
- MediaStreamTrack track, [
- MediaStream? streams1,
- MediaStream? streams2,
- MediaStream? streams3,
Implementation
RTCRtpSender addTrack(MediaStreamTrack track,
        [MediaStream? streams1,
        MediaStream? streams2,
        MediaStream? streams3]) =>
    js_util
        .callMethod(this, 'addTrack', [track, streams1, streams2, streams3]);