以下示例来自flutter.dev，我正在使用web_socket_channel插件与WebSocket连接 https://flutter.dev/docs/cookbook/networking/web-sockets

但是找不到订阅频道的选项。我有点扑朔迷离。我正在添加我的等效浏览器javascript代码以更好地理解。我想在颤抖中达到同样的效果。

等效的javascript代码->

function startChat() {
  ws = adonis.Ws("ws://127.0.0.1:3333").connect();

  ws.on("open",() => {
    $(".connection-status").addClass("connected");
    subscribeToChannel();
  });

  ws.on("error",() => {
    $(".connection-status").removeclass("connected");
  });
}

function subscribeToChannel() {
  const chat = ws.subscribe("chat");

  chat.on("error",() => {
    $(".connection-status").removeclass("connected");
  });

  chat.on("message",message => {
    // console.log(message)
    $(".messages").append(`
      <div class="message"><h3> ${message.username}</h3><p> ${message.body} </p></div>
    `);
  });
}

$("#message").keyup(function(e) {
  if (e.which === 13) {
    e.preventDefault();
    const message = $(this).getValAndClear();
    console.log(message);

    ws.getSubscription("chat").emit("message",{
      username: window.username,body: message
    });
  }
});