Variable outputFetchConst

A fetch compliant function, that wraps undici's fetch.

Behaves the same as any fetch function except:

• Sets a request header called x-request-trace-id with a random UUID;
• Sends the request, response, error and/or failure to the Trace system;
• Emits a http:request event on every call (success, error, failure).

Node and Undici realms can't be mixed: passing a Node Request with an Undici FormData body (or vice versa) throws a TypeError.