Telemetry _Controller Is Always Undefined Due To Promise Identity Loss In Record(), So FlushDetached'S Abort Is A Silent No-Op
In Telemetry.record(), the promise stored in this.queue is the result of chaining .then().catch().then() on the promise returned by submitRecord(). Because .then()/.catch() return new Promise objects and do not copy custom properties, the final promise never has the _controller property that submitRecord() attached to its returned promise. The line (prom as any)._controller = (prom as any)._controller is a no-op. Consequently, flushDetached() always sees item._controller as undefined, making the abort() call a silent no-op.
In record(), the code assigns _controller to itself after the promise has been chained. The chained promise is a different object from the original promise returned by submitRecord(), which is the only object that actually has _controller set. Thus the controller reference is lost.
1. Run next dev with telemetry enabled.
2. Call telemetry.record(event) and inspect the returned promise's _controller property.
3. Observe that _controller is always undefined, because the returned promise is the chained promise, not the original submitRecord() promise.
Store the original promise returned by submitRecord() in a local variable sourcePromise before chaining. After the chained promise is created, copy the _controller property from sourcePromise to the final promise. This ensures that the promise stored in this.queue retains the controller reference, so flushDetached() can abort in-flight requests.
Edge Case Audit
This fix assumes that submitRecord() always attaches _controller to its returned promise for non-deferred records. In deferred mode, sourcePromise is Promise.resolve() and has no _controller, so the final promise will also have undefined _controller, which is safe but means no abort for deferred events. The change is minimal and synchronous; there is no concurrency risk. Rollback: revert to the original code if unexpected behavior occurs. Note that if submitRecord() is later refactored to not expose _controller directly, this copying will still yield undefined but will not break anything.
