assertEquals("Callback should only be invoked once", 1, callbackCount.get());
        assertEquals("Should receive first response", "first", receivedIndex.get());
    }

    @Test
    public void test_multipleReject_onlyFirstCounts() throws Exception {
        final Deferred<SuggestResponse> deferred = new Deferred<>();
        final AtomicInteger callbackCount = new AtomicInteger(0);