### Question:
FiscoBcosInstance { public IConsumer buildConsumer() { return new FiscoBcosBroker4Consumer(this.fiscoBcosDelegate); } FiscoBcosInstance(FiscoConfig config); IProducer buildProducer(); IConsumer buildConsumer();  }### Answer:
@Test public void testBuildConsumer() throws Exception { IConsumer iConsumer = this.fiscoBcosInstance.buildConsumer(); iConsumer.startConsumer(); Assert.assertTrue(iConsumer.isStarted()); String subscriptionId = iConsumer.subscribe(this.topicName, this.groupId, WeEvent.OFFSET_LAST, new HashMap<>(), new IConsumer.ConsumerListener() { @Override public void onEvent(String subscriptionId, WeEvent event) { } @Override public void onException(Throwable e) { } }); Thread.sleep(3000); iConsumer.unSubscribe(subscriptionId); }