[botandbang]

a_recording_stops_being_sent_once_publishing_is_cancelled (added in #317) fails most runs on macOS on main since #328 landed: 8 of 10 on 41abcae here, with all 32 MiB of the recording sent after the cancel. #328 moved cancelling a plugin's net/fetch and a set upload into Requests::run, which checks the token every 50 ms, and dropped the check the body made on every read. The host gets the plugin's $/cancel before publishing returns, then kept reading the file and sending it until the next check, which over loopback can be all of it.

Changed:

• net::streamed takes the cancel token and fails the body at the next 64 KiB chunk once it's set.
• Requests::run gives None when the token is set by the time the request finishes, so that failure reports as cancelled.
• Body::send (a plugin's net/fetch, file bodies and multipart parts) and the recording upload in sets publish --upload pass their tokens to streamed.
• A changelog line in apps/locallibrary/changes/upload-cancel-fix.md.

Nothing removed, and the test is unchanged. With the fix it passed 30 of 30 runs, and with the fix's two checks disabled it failed 8 of 10. The cancel, net, destinations, peer and upload tests in locallibrary and loclib-plugin pass (100 of 100), as do clippy and fmt.

[github-actions]

Rust coverage

From run 627. Both are held to the thresholds in .cargo/config.toml.

Tests	Lines	Functions	Regions
All	97.44% (82803/84976)	96.53% (13196/13670)	95.71% (182054/190207)
Hegel property tests alone	95.6% (81233/84976)	94.27% (12887/13670)	93.72% (178258/190207)