app.py

        # wait for end
        while True:
            peer_a_read = asyncio.async(peerA.read())
            peer_a_read.other_peer = peerB

            peer_b_read = asyncio.async(peerB.read())
            peer_b_read.other_peer = peerA

            done, pending = yield from asyncio.wait([peer_a_read, peer_b_read], return_when=asyncio.FIRST_COMPLETED)
            for task in pending:
                task.cancel()
            for task in done:
                data = task.result()
                if not data:
                    break
                # all we can get at this point is trickled ICE candidates
                candidate = parse(data)
                if candidate is None or candidate.candidate is None:
                    log.warning('Invalid candidate received!')
                    break
                task.other_peer.write(json.dumps(candidate.to_struct()))
            else:
                continue
            break