> Therefore, the most convenient place to add the new API are *transports*.

I had an inkling this was the case, but I didn't know how to go about the creation of a new protocol and transport pair.

> I'm hesitant to add this API to Transport; it somehow feels wrong to put such an implementation-specific thing there. E.g. I presume you can't do this for an UDP transport.

DTLS (basically TLS over any datagram-oriented protocol, including UDP, SCTP, etc.) exists, so this makes sense, although I don't know if asyncio supports it, but the only major protocol I can think of that uses DTLS is WebRTC.

In any case, it could potentially make sense for other transport types, if not now, then in the future.