How to Simulate a Dead Event Queue for Exception Handling Testing in Flutter App with Active Internet Connection?

Question

I'm working on a Flutter app that communicates with a server using event queues. I've implemented exception handling for scenarios like a "BAD_EVENT_QUEUE_ID" error, but I'm struggling to test it. I want to simulate a dead event queue on my device to verify that my exception handling works correctly.

void poll() async {
    final backoffMachine = BackoffMachine();

    while (true) {
      if (_debugLoopSignal != null) {
        await _debugLoopSignal!.future;
        assert(() {
          _debugLoopSignal = Completer();
          return true;
        }());
      }

      final GetEventsResult result;
      try {
        result = await getEvents(store. Connection,
            queueId: queueId, lastEventId: lastEventId);
        //store.isStale=false;
        // store.setIsStale(false);
        // print('isstale: ${store.isStale}');
      } catch (e) {

        switch (e) {
          case ZulipApiException(code: 'BAD_EVENT_QUEUE_ID'):
          //  store.isStale=true;
            store.exceptionMessage='Lost event queue ';
          store.setIsStale(true,store.exceptionMessage);

            assert(debugLog('Lost event queue for $store.  Replacing…'));
            await store._globalStore._reloadPerAccount(store.accountId);
            dispose();
            debugLog('… Event queue replaced.');
            return;

          case Server5xxException() || NetworkException():
            assert(debugLog('Transient error polling event queue for $store: $e\n'
                'Backing off, then will retry…'));
            // drives the connecting snackbar
            store.exceptionMessage='error polling';
            store.setIsStale(true,store.exceptionMessage);


            // TODO tell user if transient polling errors persist
            // TODO reset to short backoff eventually
            await backoffMachine.wait();
            assert(debugLog('… Backoff wait complete, retrying poll.'));
            continue;

          default:
            assert(debugLog('Error polling event queue for $store: $e\n'
                'Backing off and retrying even though may be hopeless…'));
            store.exceptionMessage='non-transient';
            store.setIsStale(true,store.exceptionMessage);

            // TODO tell user on non-transient error in polling
            await backoffMachine.wait();
            assert(debugLog('… Backoff wait complete, retrying poll.'));
            continue;
        }
      }

      final events = result.events;
      for (final event in events) {
        store.handleEvent(event);
      }
      if (events.isNotEmpty) {
        lastEventId = events.last.id;
      }
    }
  }

I've tried to trigger the exception by disconnecting from the internet, but i want to test it since my device still believes it has an internet connection, I don't get the feedback I need.

What methods or tools can I use to intentionally simulate a dead event queue on my device and verify that my exception handling code is working as expected? Additionally, how can I ensure that I'm correctly catching and handling the "BAD_EVENT_QUEUE_ID" exception?

Any insights or suggestions would be greatly appreciated. Thank you!