// in the list after any error from this proxy. If fallBackOnError is false,
	// the request will only be attempted on the next proxy if the error is
	// equivalent to os.ErrNotFound, which is true for 404 and 410 responses.
	fallBackOnError bool
}

func proxyList() ([]proxySpec, error) {
	proxyOnce.Do(func() {
		if cfg.GONOPROXY != "" && cfg.GOPROXY != "direct" {