pub async fn probe(url: &str, timeout_ms: u64) -> RendezvousOutcomeExpand description
Connect to url (wss://<host>/rtc/<key>), announce, and validate the
introduction the rendezvous sends back. Per §3.2 welcome is OPTIONAL (a
minimal rendezvous may let clients keep provisional ids) but peers is not;
and when welcome IS sent, it must arrive before peers.