Does attaching an async upgrade function cause error?

[OmGuptaIND]

I see that in uWs, you need to attach an upgrade function, but that function is supposed to be sync and every async things need to happen in res.cork, but attaching an async function didn't cause any error. So is there any downside to doing that? I don't know why the implementation is done this way. Need some context for this

 upgrade: async (
        res: uWs.HttpResponse,
        req: uWs.HttpRequest,
        context: uWs.us_socket_context_t,
      ) => {
        const upgradeAborted = { aborted: false };
        ```

[OmGuptaIND]

Spent some more time reading the docs got the answer