Raise error when concurrent to call new Tiktoken

[qkxie]

The context code is https://github.com/mckaywrigley/chatbot-ui/blob/main/pages/api/chat.ts#L21

The key problem is here:

In my frontend, I use promise.all to send 3 requests simultaneously to this backend API. I have noticed the following phenomena:

1. When running this backend with "npm run dev", everything works fine.
2. When running with "npm run build" and then "npm run start":
3. If I make a separate request to this API after the backend is started, and then the frontend sends concurrent requests, everything works fine.
4. If the frontend immediately sends concurrent requests to this backend API after it is started, it will result in the error shown in the image below.