Header:     map[string][]string(res.Header),
		Body:       res.Body,
	}

	if res.StatusCode != http.StatusOK {
		contentType := res.Header.Get("Content-Type")
		if mediaType, params, _ := mime.ParseMediaType(contentType); mediaType == "text/plain" {
			switch charset := strings.ToLower(params["charset"]); charset {
			case "us-ascii", "utf-8", "":
				// Body claims to be plain text in UTF-8 or a subset thereof.