.CORE 5 Web Api和客户端MQTT

using MQTTnet;
using MQTTnet.Client;
using MQTTnet.Client.Connecting;
using MQTTnet.Client.Disconnecting;
using MQTTnet.Client.Options;
using System;
using System.Threading.Tasks;

public class MqttClientService
{
    private IMqttClient _mqttClient;

    public async Task ConnectAsync(string serverUri, string clientId)
    {
        var factory = new MqttFactory();
        _mqttClient = factory.CreateMqttClient();

        var options = new MqttClientOptionsBuilder()
            .WithTcpServer(serverUri)
            .WithClientId(clientId)
            .Build();

        _mqttClient.ApplicationMessageReceivedHandler = new MqttApplicationMessageReceivedHandlerDelegate(e =>
        {
            Console.WriteLine("Received message: " + Encoding.UTF8.GetString(e.ApplicationMessage.Payload));
        });

        await _mqttClient.ConnectAsync(options);
    }

    public async Task PublishAsync(string topic, string payload)
    {
        var message = new MqttApplicationMessageBuilder()
            .WithTopic(topic)
            .WithPayload(payload)
            .Build();

        await _mqttClient.PublishAsync(message);
    }
}