rabbit_producer.cs

public class Publisher {
  private IModel _model;
  
  public Publisher(IConnection conn, string queueName) {
    _model = conn.CreateModel();
 
    // it's safe to declare queues that already exist as long as their properties are identical
    // this runs on initialization every time - that will ensure all of your queues exist on app startup
    model.QueueDeclare(queueName, true, false, false, null);
    
    // binds the given queue to the routingKey. We use the same string as both the queue name and routing key
    model.QueueBind(queueName, "amq.direct", queueName);
  }
  
  // serialize your message body however you want. JSON is nice because it's makes debugging a bit easier.
  public void PublishMessage(string routingKey, byte[] body)
  {
      var props = _model.CreateBasicProperties();
 
      // this is important, it tells the queue to make the message delivery 'durable'
      props.DeliveryMode = 2;
      if (props.Headers == null)
      {
          props.Headers = new Dictionary<string, object>();
      }
 
      _model.BasicPublish("amq.direct", routingKey, props, body);
  }
}