@Override
	public synchronized void stop() {
		if (this.isRunning() && null != consumer) {
			consumer.unsubscribe(topic);
			consumer.shutdown();
			this.running = false;
		}
	}
@author <a href="mailto:fangjian0423@gmail.com">Jim</a>
spring-cloud-alibaba-starters/spring-cloud-starter-stream-rocketmq/src/main/java/com/alibaba/cloud/stream/binder/rocketmq/integration/inbound/pull/RocketMQMessageSource.java