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我正在尝试启动一个简单的代码库，以使用本地蚊子代理测试 MQTTNet 的库实现其订阅者和发布者代码，随后通过 HiveMQ 的 WebSocket。

目前，这些代码位于本教程的 C# 控制台应用程序中，https ://www.youtube.com/watch?v=lcsnsj1yBs0&ab_channel=RishabhSharma ：

发布者代码

static async Task Main(string[] args)
{
    Console.WriteLine("Publisher");
    var mqttFactory = new MqttFactory();
    IMqttClient mqttClient = mqttFactory.CreateMqttClient();
    var mqttClientOptions = new MqttClientOptionsBuilder()
                            .WithClientId(Guid.NewGuid().ToString())
                            .WithTcpServer("test.mosquito.org", 1883)
                            //.WithWebSocketServer("broker.hivemq.com:8000/mqtt")
                            .WithCleanSession()
                            .Build();

    mqttClient.UseConnectedHandler(e =>
    {
        Console.WriteLine("Connected to the Broker Succesfully");
    });

    mqttClient.UseDisconnectedHandler(e =>
    {
        Console.WriteLine("Disconnected to the Broker Succesfully");
    });

   await mqttClient.ConnectAsync(mqttClientOptions);

    Console.WriteLine("Press a key to publish the message");
    Console.ReadLine();

    await PublishMessageAsyn(mqttClient);

    await mqttClient.DisconnectAsync();
}
private static async Task PublishMessageAsyn(IMqttClient mqttClient)
{
    string messagePayload = "Hello!";
    var publishMessage = new MqttApplicationMessageBuilder()
                        .WithTopic("astar/vfarmproject")
                        .WithPayload(messagePayload)
                        .WithAtLeastOnceQoS()
                        .Build();
    if (mqttClient.IsConnected)
    {
        await mqttClient.PublishAsync(messagePayload);
        Console.WriteLine($"Published Message - {messagePayload}");
    }
}

订户代码

static async Task Main(string[] args)
{
    Console.WriteLine("Subscriber");
    var mqttFactory = new MqttFactory();
    IMqttClient mqttClient = mqttFactory.CreateMqttClient();
    var mqttClientOptions = new MqttClientOptionsBuilder()
                            .WithClientId(Guid.NewGuid().ToString())
                            .WithTcpServer("test.mosquito.org", 1883)
                            //.WithWebSocketServer("broker.hivemq.com:8000/mqtt")
                            .WithCleanSession()
                            .Build();

    mqttClient.UseConnectedHandler(async e =>
    {
        Console.WriteLine("Connected to the Broker Succesfully");
        var topicFilter = new TopicFilterBuilder()
                            .WithTopic("astar/vfarmproject")
                            .Build();
        await mqttClient.SubscribeAsync(topicFilter);
    });

    mqttClient.UseDisconnectedHandler(e =>
    {
        Console.WriteLine("Disconnected to the Broker Succesfully");
    });

    mqttClient.UseApplicationMessageReceivedHandler(e =>
    {
        Console.WriteLine($"Received Message - {Encoding.UTF8.GetString(e.ApplicationMessage.Payload)}");
    });

    await mqttClient.ConnectAsync(mqttClientOptions, CancellationToken.None);

    Console.ReadLine();

    await mqttClient.DisconnectAsync();
}

尝试await mqttClient.ConnectAsync(mqttClientOptions);使用以下堆栈跟踪执行时引发异常：

Exception thrown: 'MQTTnet.Exceptions.MqttCommunicationTimedOutException' in System.Private.CoreLib.dll
An exception of type 'MQTTnet.Exceptions.MqttCommunicationTimedOutException' occurred in System.Private.CoreLib.dll but was not handled in user code
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