Perform a fetch request.
the URL to fetch.
optional FetchOptions.
the Response. Rejects the same way native fetch() does: a genuine network failure
rejects with a TypeError, a timeout (via FetchOptions.timeoutMs) rejects with a
DOMException whose name is "TimeoutError", and a shutdown-triggered abort rejects with a
DOMException whose name is "AbortError".
Service allowing a Command to perform a
fetch()request, with an optional timeout and shutdown signals gracefully aborting the request.