Custom Authorization Header name

[Cybertron01Z]

Our project uses an Azure Static Web App, which is linked to Azure Functions. The issue with this setup is, that the Authorization header is hijacked by Azure, to authenticate between SWA and the Functions (see Azure/static-web-apps#34).
Since I am currently integrating an OIDC server on Azure Functions (it is a simplified version, for mocking on our DEV env), we need to send the Bearer Toke for the /userinfo endpoint on a different header (e.g. X-Custom-Authorization).

But from what I can see, the header is not configurable: https://github.com/authts/oidc-client-ts/blob/main/src/JsonService.ts#L89-L92

Would it be possible to make this configurable?
I have tried with the extraHeaders config, but getting the accessToken is async, which means this won't work.

Is there another way this could work today already? If not would it be ok, if I create a PR with the change?

Thanks anyways for a great project :)