-(void) connect {
    mqttClient=[[MqttClientEx alloc] initWithClientId:@"some_unique_id"];
    mqttClient.host=MQTT_SERVER;
    mqttClient.username=MQTT_USERNAME;
    mqttClient.password=MQTT_PASSWORD;

    [mqttClient connectWithCompletionHandler:^(MQTTConnectionReturnCode code) {
        NSLog(@"mqtt is connected");
        mqttClient.keepAlive = 0;
        [[NSNotificationCenter defaultCenter] postNotificationName:MQTT_CONNECTED object:nil];
    }];

    mqttClient.disconnectionHandler=^(NSUInteger code)
    {
        NSLog(@"mqtt is disconnected");
    };

}

-(void) example {
    [mqttClient subscribe:@"a" withTag:@"tag1" wittMessageHandler:^(MQTTMessage *message) {

    } withCompletionHandler:nil];

    [mqttClient subscribe:@"a" withTag:@"tag2" wittMessageHandler:^(MQTTMessage *message) {

    } withCompletionHandler:nil];

}

-(void) stop {
    mqttClient.keepAlive = 0;
}