c, err = l.Listener.Accept()
	if err == nil {
		l.mu.Lock()
		*l.last = c
		l.mu.Unlock()
	}
	return
}

// TestIdentityResponse verifies that a handler can unset
func TestIdentityResponse(t *testing.T) { run(t, testIdentityResponse) }
func testIdentityResponse(t *testing.T, mode testMode) {
	if mode == http2Mode {
		t.Skip("https://go.dev/issue/56019")
	}