Log error when a queue consumer gets aborted

To help debug the problem where queue consumer isolates can time out
unexpectedly.

src/workerd/api/queue.c++

@@ -568,10 +568,10 @@ kj::Promise<WorkerInterface::CustomEvent::Result> QueueCustomEventImpl::run(
   auto result = co_await incomingRequest->finishScheduled();
   bool completed = result == IoContext_IncomingRequest::FinishScheduledResult::COMPLETED;
 
-  // Log some debug info if the request timed out.
+  // Log some debug info if the request timed out or was aborted.
   // In particular, detect whether or not the users queue() handler function completed
   // and include info about other waitUntil tasks that may have caused the request to timeout.
-  if (result == IoContext_IncomingRequest::FinishScheduledResult::TIMEOUT) {
+  if (!completed) {
     kj::String status;
     if (queueEventHolder->event.get() == nullptr) {
       status = kj::str("Empty");
@@ -591,9 +591,24 @@ kj::Promise<WorkerInterface::CustomEvent::Result> QueueCustomEventImpl::run(
         }
       }
     }
-    auto scriptId = incomingRequest->getContext().getWorker().getScript().getId();
-    auto tasks = incomingRequest->getContext().getWaitUntilTasks().trace();
-    KJ_LOG(WARNING, "NOSENTRY queue event hit timeout", scriptId, status, tasks);
+    auto& ioContext = incomingRequest->getContext();
+    auto scriptId = ioContext.getWorker().getScript().getId();
+    auto tasks = ioContext.getWaitUntilTasks().trace();
+    if (result == IoContext_IncomingRequest::FinishScheduledResult::TIMEOUT) {
+      KJ_LOG(WARNING, "NOSENTRY queue event hit timeout", scriptId, status, tasks);
+    } else if (result == IoContext_IncomingRequest::FinishScheduledResult::ABORTED) {
+      // Attempt to grab the error message to understand the reason for the abort.
+      // Include a timeout just in case for some unexpected reason the onAbort promise hasn't
+      // already rejected.
+      kj::String abortError;
+      co_await ioContext.onAbort()
+          .then([] {}, [&abortError](kj::Exception&& e) {
+        abortError = kj::str(e);
+      }).exclusiveJoin(ioContext.afterLimitTimeout(1 * kj::MICROSECONDS).then([&abortError]() {
+        abortError = kj::str("onAbort() promise has unexpectedly not yet been rejected");
+      }));
+      KJ_LOG(WARNING, "NOSENTRY queue event aborted", abortError, scriptId, status, tasks);
+    }
   }
 
   co_return WorkerInterface::CustomEvent::Result{