net/http: Allow configuring write timeout of header/body on transport

[nhooyr]

Not sure how important this is but given *http.Server has fields for this, maybe *httputil.ReverseProxy should as well.

[meirf]

Have you considered setting whatever you want on http.Server and then setting the reverse proxy as the Server's Handler? Do you see any concerns with that?

[nhooyr]

Just realized I can just cancel the request context to make this work. All is good.