assertEquals(1, first.size());
        List<LogNotificationEvent> second = helper.drainAll();
        assertTrue(second.isEmpty());
    }

    @Test
    public void test_offer_bufferCapacity() {
        LogNotificationHelper helper = new LogNotificationHelper();
        // Default buffer size is 1000; offer more than that
        for (int i = 0; i < 1100; i++) {