t.Errorf("got response %q, want %q", got, want)
	}
}

func Test1xxHeadersNotModifiedAfterRoundTrip(t *testing.T) {
	// https://go.dev/issue/65123: We use httptrace.Got1xxResponse to capture 1xx responses
	// and proxy them. httptrace handlers can execute after RoundTrip returns, in particular
	// after experiencing connection errors. When this happens, we shouldn't modify the

				return nil, errors.New("net/http: too many 1xx informational responses")
			}
			pc.readLimit = pc.maxHeaderResponseSize() // reset the limit
			if trace != nil && trace.Got1xxResponse != nil {
				if err := trace.Got1xxResponse(resCode, textproto.MIMEHeader(resp.Header)); err != nil {
					return nil, err
				}
			}
			continue
		}
		break
	}
	if resp.isProtocolSwitch() {

			if v, ok := header[h]; ok {
				t.Errorf("%s is %q; must not be sent", h, v)
			}
		}
	}

	var respCounter uint8
	trace := &httptrace.ClientTrace{
		Got1xxResponse: func(code int, header textproto.MIMEHeader) error {
			switch respCounter {
			case 0:
				checkLinkHeaders(t, []string{"</style.css>; rel=preload; as=style", "</script.js>; rel=preload; as=script"}, header["Link"])

	resTrailer *Header // client's Response.Trailer
}

var http2got1xxFuncForTests func(int, textproto.MIMEHeader) error

// get1xxTraceFunc returns the value of request's httptrace.ClientTrace.Got1xxResponse func,
// if any. It returns nil if not set or if the Go version is too old.
func (cs *http2clientStream) get1xxTraceFunc() func(int, textproto.MIMEHeader) error {
	if fn := http2got1xxFuncForTests; fn != nil {

	var got strings.Builder

	req, _ := NewRequest("GET", cst.ts.URL, nil)
	req = req.WithContext(httptrace.WithClientTrace(context.Background(), &httptrace.ClientTrace{
		Got1xxResponse: func(code int, header textproto.MIMEHeader) error {
			fmt.Fprintf(&got, "1xx: code=%v, header=%v\n", code, header)
			return nil
		},
	}))
	res, err := cst.c.Do(req)
	if err != nil {
		t.Fatal(err)