Share screen and audio/video from single peer connection!

If you are using Chrome version <= 71 then this chrome-extension is required.

1. It is one-way streaming; flowing from peer1 to peer2.
2. peer1 attached both screen capturing stream; and audio/video stream.
3. On "peer2" side; "ontrack" event is fired two times.
4. First time; "ontrack" returned audio/video stream; and last time it returned screen capturing stream.
5. Basically it is multi-streams attachment demo.
6. You can get same functionality via "renegotiation" process; supported by RTCMultionnection v1.3 and v1.4

// attaching audio/video stream
offerer.addTrack(video_stream.getTracks()[0], video_stream);
					
// attaching screen capturing stream
offerer.addTrack(screen_stream.getTracks()[0], screen_stream);