// https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/If-None-Match#directives
	if clientCachedHash := req.Header.Get("If-None-Match"); quotedHash == clientCachedHash {
		w.WriteHeader(http.StatusNotModified)
		return
	}

	responsewriters.WriteObjectNegotiated(
		serializer,
		DiscoveryEndpointRestrictions,
		targetGV,
		w,
		req,
		http.StatusOK,
		object,
		true,
	)
}

	if ifNoneMatchETagHeader != "" {
		if isETagEqual(objInfo.ETag, ifNoneMatchETagHeader) {
			// If the object ETag matches with the specified ETag.
			writeHeadersPrecondition(w, objInfo)
			w.WriteHeader(http.StatusNotModified)
			return true
		}
	}

	// If-Modified-Since : Return the object only if it has been modified since the specified time,
	// otherwise return a 304 (not modified).

	second, secondBody, _ := fetchPath(manager, "application/json", discoveryPath, initial.Header.Get("ETag"))

	assert.Equal(t, http.StatusOK, initial.StatusCode, "initial response should be 200 OK")
	assert.Equal(t, http.StatusNotModified, second.StatusCode, "second response should be 304 Not Modified")
	assert.Equal(t, initial.Header.Get("ETag"), second.Header.Get("ETag"), "ETag of both requests should be equal")

	"Moved Permanently":               http.StatusMovedPermanently,
	"Found":                           http.StatusFound,
	"See Other":                       http.StatusSeeOther,
	"Not Modified":                    http.StatusNotModified,
	"Use Proxy":                       http.StatusUseProxy,
	"Temporary Redirect":              http.StatusTemporaryRedirect,
	"Permanent Redirect":              http.StatusPermanentRedirect,

	delete(h, "Content-Length")
	delete(h, "Content-Encoding")
	if h.Get("Etag") != "" {
		delete(h, "Last-Modified")
	}
	w.WriteHeader(StatusNotModified)
}

// checkPreconditions evaluates request preconditions and reports whether a precondition
// resulted in sending StatusNotModified or StatusPreconditionFailed.
func checkPreconditions(w ResponseWriter, r *Request, modtime time.Time) (done bool, rangeHeader string) {

				return
			}

			okSt := (ci.StatusCode == http.StatusOK || ci.StatusCode == http.StatusPartialContent ||
				ci.StatusCode == http.StatusPreconditionFailed || ci.StatusCode == http.StatusNotModified)
			if okSt {
				ci.WriteHeaders(w, func() {
					// set common headers
					setCommonHeaders(w)
				}, func() {
					okSt := (ci.StatusCode == http.StatusOK || ci.StatusCode == http.StatusPartialContent)

	c.Assert(err, nil)
	// Since the "If-Modified-Since" header was ahead in time compared to the actual
	// modified time of the object expecting the response status to be http.StatusNotModified.
	c.Assert(response.StatusCode, http.StatusNotModified)

	// Again, obtain the object info.
	// This time setting "If-Unmodified-Since" to a time after the object is modified.

func Test304Responses(t *testing.T) { run(t, test304Responses) }
func test304Responses(t *testing.T, mode testMode) {
	cst := newClientServerTest(t, mode, HandlerFunc(func(w ResponseWriter, r *Request) {
		w.WriteHeader(StatusNotModified)
		_, err := w.Write([]byte("illegal body"))
		if err != ErrBodyNotAllowed {
			t.Errorf("on Write, expected ErrBodyNotAllowed, got %v", err)
		}
	}))
	defer cst.close()
	res, err := cst.c.Get(cst.ts.URL)

	}
	b, err := io.ReadAll(resp.Body)
	resp.Body.Close()
	if err != nil {
		t.Fatal("reading Body:", err)
	}
	if len(b) != 0 {
		t.Errorf("non-empty body")
	}
	if g, e := resp.StatusCode, StatusNotModified; g != e {
		t.Errorf("status mismatch: got %d, want %d", g, e)
	}
	// HTTP1 transport sets ContentLength to 0.
	if g, e1, e2 := resp.ContentLength, int64(-1), int64(0); g != e1 && g != e2 {

	if string(all) != "hi" {
		t.Errorf("Body = %q; want hi", all)
	}
}

// Issue 6157, Issue 6685
func TestCodesPreventingContentTypeAndBody(t *testing.T) {
	for _, code := range []int{StatusNotModified, StatusNoContent} {
		ht := newHandlerTest(HandlerFunc(func(w ResponseWriter, r *Request) {
			if r.URL.Path == "/header" {
				w.Header().Set("Content-Length", "123")
			}
			w.WriteHeader(code)