LOG.info("Testing now with Client ID: {}", clientId);
mqtt.setClientId(clientId);
mqtt.setCleanSession(!"durable".equals(clientId));
BlockingConnection connection = mqtt.blockingConnection();
connection.connect();
// set retained message and check
connection.publish(TOPICA, RETAIN.getBytes(), QoS.EXACTLY_ONCE, true);
connection.subscribe(new Topic[]{new Topic(TOPICA, QoS.AT_LEAST_ONCE)});