final CommonServerMessageBlockRequest next = chain.getNext();
                if (log.isTraceEnabled()) {
                    log.trace(String.format("%s costs %d avail %d (%s)", chain.getClass().getName(), cost, this.credits.availablePermits(),
                            this.name));
                }

            latch.countDown();
        }).error(t -> {
            t.printStackTrace();
            latch.countDown();
            fail();
        });
        latch.await();
        assertEquals(num, numObInputDoc.get());

        SuggestResponse response = suggester.suggest().setQuery("test").setSuggestDetail(true).execute().getResponse();
        assertEquals(1, response.getNum());
    }