- worker for webrtc
---------- sdp/candidate ---------- sdp/candidate ----------
| peer A | --------------> | signal | --------------> | peer B |
| | <------------- | server | <------------- | |
---------- (websocket) ---------- (websocket) ----------
| | | |
| | media track(rtp) | |
| <--------------------------------------------------------> |
| data channel(sctp) |
<-------------------------------------------------------------->