WellknownRequestFn: (
    url: string,
) => PromiseLike<WellknownRequestResult> | WellknownRequestResult

A function that fetches a URL and returns { data } or { error }.

This is the injection point for custom HTTP transports. When used with RTK Query, pass the baseQuery from queryFn directly.

The function should return { data } on success or { error } on failure. Returning both as undefined is a type error.

Type declaration