http.Client ignores Transport

[adamreese]

Hi friends!

I'm trying to use a custom Transport on a http.Client but the RoundTrip is never called. It worked as expected prior to v0.29.

Here's an example:

type Transport struct{}

func (r *Transport) RoundTrip(req *http.Request) (*http.Response, error) {
	fmt.Println("never called")
	return nil, nil
}

func doIt() {
	client := &http.Client{
		Transport: &Transport{},
	}
	req, _ := http.NewRequest(http.MethodGet, "https://random-data-api.fermyon.app/animals/json", nil)
	client.Do(req)
}

Thanks for the great work on this project!