mqtt客户端始终不接收消息

Question

我有一个简单的2控制台应用程序，该应用程序使用System.Net.Mqtt.Server -Version 0.5.42-beta和System.Net.Mqtt-Version 0.5.42-beta软件包进行通讯。有时客户端没有收到消息。但是我正在使用Qos.ExactlyOnce在这里是什么问题？

有什么建议吗？

mqtt服务器具有专用客户端，该客户端负责向客户端发送消息

class Program
    {
        static void Main(string[] args)
        {
            Task.Run(() => testAsync()).GetAwaiter();

            Console.ReadLine();
        }

        private static async Task testAsync()
        {
            var configuration = new MqttConfiguration();

            IMqttServer mqttServer = MqttServer.Create(configuration);

            mqttServer.ClientConnected += MqttServer_ClientConnected;

            mqttServer.ClientDisconnected += MqttServer_ClientDisconnected;

            mqttServer.MessageUndelivered += MqttServer_MessageUndelivered;

            mqttServer.Stopped += MqttServer_Stopped;

            mqttServer.Start();

            var client = mqttServer.CreateClientAsync().GetAwaiter().GetResult();

            while (true)
            {
                Console.WriteLine("1- send message");

                string key = Console.ReadLine();

                await client.PublishAsync(new MqttApplicationMessage("topic", Encoding.ASCII.GetBytes(key)), MqttQualityOfService.ExactlyOnce, true);

                Console.WriteLine($"send msg : {key} , topic : topic");
            }
        }

        private static void MqttServer_Stopped(object sender, MqttEndpointDisconnected e)
        {

        }

        private static void MqttServer_MessageUndelivered(object sender, MqttUndeliveredMessage e)
        {
            if(e.Message.Payload != null)
            {
                string message = Encoding.ASCII.GetString(e.Message.Payload);

                Console.WriteLine($"Received message: {message}, from : {e.SenderId}");
            }
        }

        private static void MqttServer_ClientDisconnected(object sender, string e)
        {
            Console.WriteLine("A user disconnected.");
        }

        private static void MqttServer_ClientConnected(object sender, string e)
        {
            Console.WriteLine("A user connected.");
        }
    }

mqtt客户端只是获取消息并显示在控制台上。

class Program
    {
        static void Main(string[] args)
        {
            Task.Run(() => test()).GetAwaiter();

            Console.ReadLine();
        }

        static async void test()
        {
            try
            {
                var configuration = new MqttConfiguration();

                configuration.MaximumQualityOfService = MqttQualityOfService.ExactlyOnce;

                var client = await MqttClient.CreateAsync("172.16.71.188", configuration);

                await client.ConnectAsync(new MqttClientCredentials("testUser"));

                await client.SubscribeAsync("topic", MqttQualityOfService.ExactlyOnce);

                while (true)
                {

                    using (client.MessageStream.Subscribe(asd => Console.WriteLine($"topic: {asd.Topic}, msg: {Encoding.ASCII.GetString(asd.Payload)}")))
                    {

                    }
                }

            }
            catch (Exception ex)
            {

            }
        }