python flask-socketIO socket.io 报400错误
The client is using an unsupported version of the Socket.IO or Engine.IO protocols (further occurrences of this error will be logged with level INFO)
218.104.71.43 - - [17/Dec/2020 02:18:09] "GET /socket.io/?EIO=3&transport=polling&t=1608142688486-0 HTT...