var mqttFactory = new MqttFactory();        using var mqttClient = mqttFactory.CreateMqttClient();        var clientOptionBuilder = new MqttClientOptionsBuilder();        clientOptionBuilder.WithTcpServer(Config.Url);        clientOptionBuilder.WithClientId(CoreCommand.Common.Guid.NewGuid());        clientOptionBuilder.WithCleanSession();        var mqttClientOptions = clientOptionBuilder.Build();        // Setup message handling before connecting so that queued messages        // are also handled properly. When there is no event handler attached all        // received messages get lost.        mqttClient.ApplicationMessageReceivedAsync += e =>        {            Console.WriteLine($"Received message {Encoding.UTF8.GetString(e.ApplicationMessage.PayloadSegment)}");            return Task.CompletedTask;        };        await mqttClient.ConnectAsync(mqttClientOptions, CancellationToken.None);        await mqttClient.SubscribeAsync(Config.Topic);        while (true)        {            Thread.Sleep(1000);        }