c0b9437ab6
Fix lost logcontext when using `timeout_deferred(...)` and things actually timeout. Fix https://github.com/element-hq/synapse/issues/19087 (our HTTP client times out requests using `timeout_deferred(...)` Fix https://github.com/element-hq/synapse/issues/19066 (`/sync` uses `notifier.wait_for_events()` which uses `timeout_deferred(...)` under the hood) ### When/why did these lost logcontext warnings start happening? ``` synapse.logging.context - 107 - WARNING - sentinel - Expected logging context call_later but found POST-2453 synapse.logging.context - 107 - WARNING - sentinel - Expected logging context call_later was lost ``` In https://github.com/element-hq/synapse/pull/18828, we switched `timeout_deferred(...)` from using `reactor.callLater(...)` to [`clock.call_later(...)`](https://github.com/element-hq/synapse/blob/3b59ac3b69f6a2f73a504699b30313d8dcfe4709/synapse/util/clock.py#L224-L313) under the hood. This meant it started dealing with logcontexts but our `time_it_out()` callback didn't follow our [Synapse logcontext rules](https://github.com/element-hq/synapse/blob/3b59ac3b69f6a2f73a504699b30313d8dcfe4709/docs/log_contexts.md).