// Add listeners concurrently from multiple threads
        for (int i = 0; i < numThreads; i++) {
            executor.submit(() -> {
                try {
                    fesenClient.addOnConnectListener(() -> callbackCount.incrementAndGet());
                } finally {
                    latch.countDown();
                }
            });
        }

        latch.await(5, TimeUnit.SECONDS);