feat(kio): add a poll-native Deadline and adopt it in moq-net

[kixelated]

Summary

Six sites in moq-net hand-rolled a wall-clock deadline inside a kio::wait closure. Each pinned an async block whose None arm was std::future::pending(), then fused it with a separate fired flag and an is_some() guard:

let mut sleep = std::pin::pin!(async {
    match deadline {
        Some(at) => web_async::time::sleep(at.saturating_duration_since(web_async::time::Instant::now())).await,
        None => std::future::pending().await,
    }
});
let mut fired = false;
kio::wait(|waiter| {
    ...
    if deadline.is_some() && !fired && waiter.poll_future(sleep.as_mut()).is_ready() { fired = true; }
    match fired { true => Poll::Ready(Step::Expired), false => Poll::Pending }
})

kio::time::Deadline collapses that to deadline.set(at) plus deadline.poll(waiter).

• Both clock backends behind web_async::time (tokio natively, wasmtimer in the browser) already expose Sleep::is_elapsed and Sleep::reset, so the fuse comes for free and re-arming reuses the allocation instead of boxing a fresh future every loop turn.
• Deadline::set is a no-op for the instant it already holds, which is what lets the linger loops in origin.rs recompute and re-set their deadline every turn without restarting the countdown. The (true, at) => at arm depends on this.
• Constructing the inner Sleep is deferred to the first poll: on native it panics without a live tokio time driver, and only the poll is guaranteed to run inside the executor. So new/set stay callable anywhere, and the runtime requirement lands exactly where it does today.
• The probe interval in lite/publisher.rs no longer pins interval.tick(). Interval::poll_tick is already poll-native on both backends and needs no wrapper.

kio::tokio::Sleep is superseded: native-only, no re-arm, no disarm, no fuse. It had no callers anywhere, and nothing in the workspace enabled the tokio feature. Hidden and deprecated here; the removal (plus dropping the optional tokio dependency) is a breaking change to a published crate and belongs on dev as a follow-up.

Net -34 lines across the converted sites.

Public API changes

All additive, so this targets main.

• Added kio::time module behind a new time cargo feature (dep:web-async).
• Added kio::time::Deadline with new, at, after, set, deadline, poll, wait, plus Default and Debug.
• Added kio::time::{Instant, Duration} re-exports from web_async::time.
• Deprecated kio::tokio::Sleep (#[deprecated]) and hid kio::tokio (#[doc(hidden)]). Not a removal, so not breaking. Verified the warning reaches a caller rather than being swallowed by the #[allow(deprecated)] on the impl block.
• moq-net gains no public surface; all six converted sites are private.

Test plan

• 7 new Deadline tests under #[tokio::test(start_paused = true)], covering firing, disarmed-never-fires, fused-once-elapsed, idempotent re-arm, deferred re-arm through Sleep::reset, disarm mid-countdown, and re-arm after disarm.
• just fix clean, just rs check clean (clippy -D warnings, cargo fmt --check, rustdoc -D warnings, cargo shear, cargo sort).
• cargo test -p kio --all-features: 26 pass. cargo test -p moq-net: 557 pass. Full just rs test: 1941 pass.
• cargo check -p kio --features time --target wasm32-unknown-unknown builds, pulling wasmtimer as expected. The moq-net wasm build fails on a pre-existing getrandom backend error, identical with these changes stashed.

Unrelated failure seen while testing

moq-srt's accepted_socket_sends_a_burst_larger_than_srt_tokio_default failed once in the full run. It is pre-existing and not caused by this change: on a stashed tree it fails 2 of 8 consecutive runs, versus 1 of 5 here. It sends 1024 messages over a real SRT/UDP loopback socket and asserts delivery inside a fixed 3-second wall-clock budget on real timers, so it is timing-sensitive under load. Tracked separately rather than papered over with a longer timeout.

Cross-Package Sync

No rows apply. No wire format, moq-ffi, CLI, or relay config surface changed, and moq-net's public API is untouched.

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(Written by Opus 5)

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Review details

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: ac47a712-8de5-4855-8e3b-9767b63461d6

📥 Commits

Reviewing files that changed from the base of the PR and between b2f8918 and 5cdbaf0.

📒 Files selected for processing (2)

• rs/kio/src/time.rs
• rs/kio/src/tokio.rs

Walkthrough

Adds a feature-gated kio::time::Deadline backed by web-async, with re-arming, disarming, fused polling, async waiting, and tests. The existing Tokio Sleep type is deprecated. moq-net enables the new feature and migrates request timeouts, alias resolution, probe intervals, route announcement linger handling, front expiry, and track idle linger handling to deadline or direct interval polling.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly summarizes the main change: adding a poll-native Deadline in kio and using it in moq-net.
Description check	✅ Passed	The description is directly related to the changeset and accurately explains the new Deadline API and its adoption.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

✨ Simplify code

• Create PR with simplified code
• Commit simplified code in branch claude/kio-wait-polling-refactor-49f5fd

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Actionable comments posted: 3

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@rs/kio/src/time.rs`:
- Line 13: Add a doc comment immediately above the public re-export of Duration
and Instant explaining that these types come from web_async::time and
documenting the dependency’s major-version coupling. Keep the existing re-export
unchanged.
- Around line 53-56: Update Time’s after method to use checked Instant
arithmetic instead of Instant::now() + duration. Mirror the existing origin.rs
pattern with an inlined checked_add result, preserving the deadline behavior
while ensuring non-representable durations never panic.

In `@rs/kio/src/tokio.rs`:
- Around line 16-19: Add the #[doc(hidden)] attribute to the deprecated public
Sleep struct, alongside its existing #[deprecated(note = "...")] attribute, so
the item is excluded from generated documentation while preserving the
deprecation notice.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: c4b97578-3c6d-4edd-b521-b8ecbad9d810

📥 Commits

Reviewing files that changed from the base of the PR and between 1c2584f and b2f8918.

⛔ Files ignored due to path filters (1)

• Cargo.lock is excluded by !**/*.lock

📒 Files selected for processing (9)

• rs/kio/Cargo.toml
• rs/kio/src/lib.rs
• rs/kio/src/time.rs
• rs/kio/src/tokio.rs
• rs/moq-net/Cargo.toml
• rs/moq-net/src/ietf/control.rs
• rs/moq-net/src/ietf/subscriber.rs
• rs/moq-net/src/lite/publisher.rs
• rs/moq-net/src/model/origin.rs