fix(tokio)!: keep the transport that won the connect race

doc/concept/transport.md

@@ -42,9 +42,8 @@ connection (`wss://`) and keep whichever wins. A small multiplexer,
 [qmux](/draft/qmux-websocket), carries MoQ streams over the socket. It works
 everywhere but cannot escape TCP head-of-line blocking, so priority and resets
 only help once bytes leave the TCP queue. The fallback is automatic in every
-client; the relay enables it with `[web.https]`. A native Rust client that
-lands on WebSocket keeps dialing QUIC and moves the session over once QUIC
-succeeds.
+client; the relay enables it with `[web.https]`. A session that lands on
+WebSocket stays there until it ends; the next connect races again.
 
 ## Raw QUIC (native)
 

quest/m0/README.md

@@ -59,7 +59,7 @@ Interop on main (2026-10-13): the cross-client matrix failed with `unroutable`
 whenever WebSocket won the connect race: since #5294, #4180's upgrade
 retired epochless handles before its held `Restart` reached anyone. Handles
 now retire only once it is deliverable. First-party consumers following it
-moved to m1 (maintainer, 2026-10-13), since the upgrade is being removed.
+moved to m1 (maintainer, 2026-10-13), since the upgrade is removed.
 
 Crashes (2026-10-13, #5407): a publisher on a host whose wall clock reads
 before 2020 panics, and `panic = "abort"` turned any library panic into a
@@ -84,5 +84,4 @@ have fixes on `main`: macOS tests (#5335), drill-sensitivity (#5338), loom
 - [web-transport releases the qmux fixes](/quest/m0/qmux-credit-upstream.md) - waiting on moq-dev/web-transport#412 and #413 to merge and ship, which qmux credit bumps to
 - [qmux credit](/quest/m0/qmux-credit.md) - qmux returns connection credit for dropped and stopped streams and delivers its close frame, on both lines
 - [Broadcast epochs](/quest/m0/broadcast-epoch/README.md) - every first-party publisher that can restart mints a fresh route epoch, the newest wins a path, and only routes with the same epoch resume a subscription
-- [Keep the winning transport](/quest/m0/drop-ws-upgrade.md) - a connection stays on the transport that won the race; the WebSocket-to-QUIC upgrade and its epochless `Restart` are removed
 - [Parked drain](/quest/m0/parked-drain.md) - draining parked groups after a cap rise, as a same-epoch relay handover causes, is near-linear in the backlog, not quadratic

quest/m1/restart-followers.md

@@ -11,13 +11,13 @@ then costs a long-lived consumer nothing but the restart.
 ## Plan
 
 Moved to m1 on 2026-10-13 (maintainer): the WebSocket-to-QUIC upgrade is
-being removed (separate m0 quest), so an epochless Restart no longer follows
+removed, so an epochless Restart no longer follows
 every connect; it remains for GOAWAY drains and publisher replacement.
 
 The origin side is done: a handle resolved through a peer keeps serving new
 requests while the peer's epochless replacement is held, and refuses them
 with `Unroutable` only once the `Restart` is deliverable (`Release` in `rs/moq-net/src/model/origin.rs`,
-`rs/moq-net/tests/upgrade.rs`). So a consumer that never follows `Restart`
+`rs/moq-net/tests/replacement.rs`). So a consumer that never follows `Restart`
 works through the hold (300 ms by default), and its open subscriptions stay
 sticky on the old session until it closes, where they end cleanly. A
 consumer that opens a request after the hold, or reads past the old
@@ -45,9 +45,9 @@ Audit and fix:
 - The interop clients under `test/interop/clients`, where they resolve a
   broadcast themselves.
 
-Regression: extend `rs/moq-net/tests/upgrade.rs` (or the consumer's own
+Regression: extend `rs/moq-net/tests/replacement.rs` (or the consumer's own
 tests) so each follower reads past the old session's close after an
-epochless upgrade. Then run `just test interop --all`.
+epochless replacement. Then run `just test interop --all`.
 
 If a failing client still leaves its connection to idle out, fix that
 client's error path to close its session, as a separate commit. The C
@@ -59,5 +59,4 @@ Wire: none.
 
 ## Related
 
-- [Keep the winning transport](/quest/m0/drop-ws-upgrade.md) - removes the upgrade, so `Restart` no longer follows every WebSocket connect
 - [Broadcast epochs](/quest/m0/broadcast-epoch/README.md) - the players that already follow `Restart`

quest/m1/slow-source.md

@@ -6,7 +6,7 @@ An export whose source arrives further off real time than the output's
 clock may follow ends with an error naming the measured rate, once it has
 used half its delay. It no longer drops nearly every frame for hours with
 only per-frame "missed its deadline" warnings. A short stall, such as a
-WebSocket-to-QUIC upgrade, still drops late frames and recovers.
+reconnect, still drops late frames and recovers.
 
 ## Plan
 

quest/m2/quic-sim.md

@@ -4,7 +4,7 @@
 
 The `moq-time` sim drives two `moq-quic` endpoints over in-memory datagrams
 with configurable latency, loss, reordering, and bandwidth, so QUIC behavior
-(BBR, reliable reset, stream deadlines, the transport upgrade) and MoQ over
+(BBR, reliable reset, stream deadlines, the transport race) and MoQ over
 real QUIC are tested deterministically with no sockets.
 
 ## Plan

quest/m3/quic-careful-resume.md

@@ -11,8 +11,6 @@ to slow start without hurting the path.
 ## Plan
 
 Decided in the 2026-10-10 audit: scope this to remembered QUIC connections.
-Transferring TCP estimates into a WebSocket-to-QUIC upgrade is out of scope;
-that upgrade starts without a seed.
 
 Follow the shape of draft-ietf-ccwg-careful-resume: the sender keeps a
 per-destination record of the last validated bandwidth estimate and minimum

quest/m3/uring-tcp/README.md

@@ -34,9 +34,8 @@ number is what justifies the rest of the line.
 
 Decided in the 2026-09-30 audit: moved to m2, since no fleet demand asks
 for ring TCP. (Decided 2026-10-13: the WebSocket-to-QUIC upgrade that would
-have shrunk the WebSocket hot path is being removed by
-[Keep the winning transport](/quest/m0/drop-ws-upgrade.md), so a WebSocket
-session will stay on TCP for its lifetime.)
+have shrunk the WebSocket hot path is removed, so a WebSocket session stays
+on TCP for its lifetime.)
 
 Decided 2026-10-08: moved to m3. No fleet demand asks for ring TCP; the
 ablation stays the gate for the rest of the line.

rs/moq-net/src/client.rs

@@ -229,7 +229,6 @@ impl Client {
 			crate::session::Handles {
 				goaway: start.goaway,
 				auth: start.auth,
-				setup: start.setup,
 				estimate: Some(start.estimate),
 			},
 		))
@@ -292,7 +291,7 @@ impl Client {
 				// The peer's SETUP decides whether AUTH is negotiated. A handle that does not
 				// offer it keeps the option out of our SETUP and presents no credential.
 				let auth = crate::auth::Handle::new(self.extensions.auth);
-				let (protocol, goaway, setup) = ietf::start(ietf::Config {
+				let (protocol, goaway) = ietf::start(ietf::Config {
 					runtime: runtime.clone(),
 					limits: self.limits,
 					session: session.clone(),
@@ -323,7 +322,6 @@ impl Client {
 					crate::session::Handles {
 						goaway,
 						auth,
-						setup,
 						estimate: None,
 					},
 				));
@@ -418,7 +416,7 @@ impl Client {
 			.copied()
 			.ok_or(Error::Version)?;
 
-		let (recv_bw, protocol, goaway, auth, setup, estimate) = match version {
+		let (recv_bw, protocol, goaway, auth, estimate) = match version {
 			Version::Lite(v) => {
 				let stream = stream.with_version(v);
 				let start = lite::start(lite::Config {
@@ -444,7 +442,6 @@ impl Client {
 					crate::driver::Protocol::Lite(Box::new(start.driver)),
 					start.goaway,
 					start.auth,
-					start.setup,
 					Some(start.estimate),
 				)
 			}
@@ -466,7 +463,7 @@ impl Client {
 				// Draft 14-16 carry no AUTH, but the session is still limited through this handle.
 				let auth = crate::auth::Handle::new(false);
 				// Draft 14-16: the path rode in the bidi SETUP above, not the uni one.
-				let (protocol, goaway, setup) = ietf::start(ietf::Config {
+				let (protocol, goaway) = ietf::start(ietf::Config {
 					runtime: runtime.clone(),
 					limits: self.limits,
 					session: session.clone(),
@@ -486,7 +483,7 @@ impl Client {
 					early_unis: Vec::new(),
 					extensions: self.extensions,
 				})?;
-				(None, crate::driver::Protocol::Ietf(protocol), goaway, auth, setup, None)
+				(None, crate::driver::Protocol::Ietf(protocol), goaway, auth, None)
 			}
 		};
 
@@ -496,12 +493,7 @@ impl Client {
 			version,
 			recv_bw,
 			protocol,
-			crate::session::Handles {
-				goaway,
-				auth,
-				setup,
-				estimate,
-			},
+			crate::session::Handles { goaway, auth, estimate },
 		))
 	}
 }

rs/moq-net/src/ietf/peer.rs

@@ -52,16 +52,6 @@ impl PeerSetup {
 		}
 	}
 
-	/// Poll until the peer's SETUP arrives.
-	pub fn poll_seen(&self, waiter: &kio::Waiter) -> std::task::Poll<()> {
-		self.0
-			.poll(waiter, |peer| match peer.is_some() {
-				true => std::task::Poll::Ready(()),
-				false => std::task::Poll::Pending,
-			})
-			.map(|_| ())
-	}
-
 	/// Await the peer's SETUP.
 	///
 	/// The peer MUST send exactly one, so this resolves once that stream is read. Waits