pub async fn with_observer_task<F, R>(observer: Arc<dyn Observer>, fut: F) -> Rwhere
F: Future<Output = R>,Expand description
Async sibling of with_test_observer: install the observer in
the per-task slot for the duration of fut. This is the version
the #[obs::test] async expansion uses so that an emit on a
migrated-tokio-worker-thread still resolves to the test observer
(the per-thread slot would not be set on the destination worker).
OVERRIDE_COUNT is bumped before entering the scope and
decremented after, so the hot-path resolver actually probes the
task-local. Spec 11 ยง 3.1, KD-D3.