只有一个消费者从 RabbitMQ 上的队列接收消息

我创建了一个小演示来展示 RabbitMQ 基础知识。不幸的是，它没有按预期工作，有两个问题。我正在使用 .NET Core 3.1 和 RabbitMQ.Client 6.2.2

我创建了从任务队列接收消息的 Employee 类。第一个员工工作得很好，但如果我雇用更多员工，他们就无法工作（不接收消息）。我不明白为什么会这样。

如果我在队列中有很多消息（在启动第二个员工之前），我会看到任务队列中的所有消息在第二个启动时都得到确认，然后在很短的时间后它们再次变为未确认。有点奇怪。

但主要是：为什么其他员工不工作？

using RabbitMQ.Client;
using RabbitMQ.Client.Events;
using System;
using System.Text;
using System.Threading;

namespace DemoTasks.Employee
{

  class Employee
  {
    static void Main(string[] args)
    {

      string clientName = "Employee-" + Guid.NewGuid().ToString();

      Console.Title = clientName;
      Console.WriteLine("Moin moin");

      IConnectionFactory connectionFactory = new ConnectionFactory
      {
        HostName            = "localhost",
        Port                = 5672,
        VirtualHost         = "/",
        UserName            = "user",
        Password            = "password",
        ClientProvidedName  = clientName
      };

      using (IConnection connection = connectionFactory.CreateConnection(clientName))
      {
        using (IModel model = connection.CreateModel())
        {

          model.ExchangeDeclare("jobs", "fanout", false, false, null);
          model.QueueDeclare("tasks", true, false, false);
          model.QueueBind("tasks", "jobs", "", null);

          EventingBasicConsumer consumer = new EventingBasicConsumer(model);
          consumer.Received += OnWorkReceived;

          model.BasicConsume("tasks", false, clientName + ":OnWorkReceived", consumer);

          Console.ReadLine();

          model.Close();
        }
        connection.Close();
      }

      Console.WriteLine("Wochenende ... woooh !!!");
    } 

    private static void OnWorkReceived(object sender, BasicDeliverEventArgs e)
    {

      EventingBasicConsumer consumer = (EventingBasicConsumer)sender;
      IModel model  = consumer.Model;

      string task = Encoding.UTF8.GetString(e.Body.ToArray());

      Console.Write("working on: " + task + " ... ");

      Thread.Sleep(5000);

      Console.WriteLine("done!");
              
      model.BasicAck(e.DeliveryTag, false);
    }

  } 

}