Python Flatter客户端无法侦听服务器发出的部署在heroku上的Flask socketio

我在Heroku服务器上部署了以下flask socketio代码

from flask import Flask, request, jsonify
from flask_socketio import SocketIO

app = Flask(__name__)
app.secret_key = 'secret'

socketio = SocketIO(app,cors_allowed_origins="*",logger=True, engineio_logger=True)

app.debug = True

@app.route('/', methods=['GET'])
def index():
    return 'Welcome!'

@socketio.on('connect')
def test_connect():
    emit('connected', {'data': 'Ready'}) // client side can get this emit

@socketio.on('message')
def send_msg():
    emit('received_msg', {'data': 'Ready'}) // but client doesn't listen to this. The client side just keeps loading and the crashes.

@socketio.on('disconnect')
def test_disconnect():
    print('Client disconnected')

port = int(os.environ.get('PORT', 5000))
if __name__ == '__main__':
    socketio.run(app,debug=True,host="0.0.0.0",port=port,log_output=True)

下面是颤振客户端代码

IO.Socket socket = IO.io('https://heroku_url', <String, dynamic>{
      'transports': ['websocket']
});

socket.Connect((_) => print('disconnect'));

socket.on('connected',(data)=>print(data)); // client listens to this and prints the value

socket.on('received_msg',(data)=>print(data));  // but this doesn't listen to emit from server and the app crashes

socket.onDisconnect((_) => print('disconnect'));

IO.Socket套接字=IO.IO（'https://heroku_url', {
“传输”：['websocket']
});
socket.Connect（（)）=>打印（'disconnect'）；
socket.on（'已连接'，（数据）=>打印（数据））；//客户机侦听此消息并打印值
socket.on（'received_msg'，（data）=>print（data））；//但这不会监听服务器发出的消息，应用程序会崩溃
socket.onDisconnect（（)）=>print（'disconnect'）；

有些发射能工作，而有些不能。我不明白为什么：/。我没有使用任何房间或网络。因为只有一个房间，但我认为这不是问题所在，因为在localhost上它运行得非常好，只是在heroku服务器上没有。如果有人能告诉我哪里出错了