在async Rust（Tokio）中包装阻塞mpsc

Question

我正在尝试使用Tokio包装一个同步MQTT客户机库。代码需要通过std::sync::mpsc通道连续接收消息，并将它们发送到异步代码中。我了解如何使用spawn_blocking包装返回单个值的代码。但是如何将此应用于包装从std::sync::mpsc通道连续接收消息的循环？

let (mut tx, mut rx) = std::sync::mpsc::channel();

tokio::spawn(async move {
            let mut mqtt_options = MqttOptions::new("bot", settings.mqtt.host, settings.mqtt.port);
            let (mut mqtt_client, notifications) = MqttClient::start(mqtt_options).unwrap();

            mqtt_client.subscribe(settings.mqtt.topic_name, QoS::AtLeastOnce).unwrap();

            tokio::task::spawn_blocking(move || {
                println!("Waiting for notifications");
                for notification in notifications {
                    match notification {
                        rumqtt::Notification::Publish(publish) => {
                            let payload = Arc::try_unwrap(publish.payload).unwrap();
                            let text: String = String::from_utf8(payload).expect("Can't decode payload for notification");
                            println!("Recieved message: {}", text);
                            let msg: Message = serde_json::from_str(&text).expect("Error while deserializing message");
                            println!("Deserialized message: {:?}", msg);
                            println!("{}", msg);
                            tx.send(msg);
                        }
                        _ => println!("{:?}", notification)
                    }
                }
            });
    });

tokio::task::spawn(async move || {
    // How to revieve messages via `rx` here? I can't use tokio::sync::mpsc channels 
    // since the code that sends messages is blocking.
});

Answer 1

我在rust-lang社区发布了一个单独的帖子，并在那里得到了答案。

std::sync::mpsc::channel可以交换到tokio::sync::mpsc::unbounded_channel，它具有非异步发送方法。它解决了问题。