t.Errorf("want %q, got %q", testPayload, string(resp))
		}
		t.Log("Roundtrip:", time.Since(start))
	})

	t.Run("localToRemoteErr", func(t *testing.T) {
		const testPayload = "Hello Grid World!"
		start := time.Now()
		resp, err := remoteConn.Request(context.Background(), handlerTest2, []byte(testPayload))
		t.Log("Roundtrip:", time.Since(start))
		if len(resp) != 0 {
			t.Errorf("want nil, got %q", string(resp))
		}

		return c.roundtrip(h, req)
	}

	// Following trimming is needed for consistency between outputs with other internode traces.
	local := strings.TrimPrefix(strings.TrimPrefix(t.Local, httpsScheme), httpScheme)
	remote := strings.TrimPrefix(strings.TrimPrefix(t.Remote, httpsScheme), httpScheme)

	start := time.Now()
	body := bytesOrLength(req)
	resp, err := c.roundtrip(h, req)
	end := time.Now()

	const testPayload = "Hello Grid World!"

	gotResp := make(chan struct{})
	go func() {
		start := time.Now()
		t.Log("Roundtrip: sending request")
		resp, err := remoteConn.Request(context.Background(), handlerTest, []byte(testPayload))
		t.Log("Roundtrip:", time.Since(start), resp, err)
		gotResp <- struct{}{}
	}()
	<-gotCall
	remote.debugMsg(debugKillInbound)
	local.debugMsg(debugKillInbound)

		ctx:       ctx,
		cancelFn:  cancelFn,
		parent:    parent,
		LastPong:  time.Now().Unix(),
		BaseFlags: parent.baseFlags,
	}
}

// roundtrip performs a roundtrip, returning the first response.
// This cannot be used concurrently.
func (m *muxClient) roundtrip(h HandlerID, req []byte) ([]byte, error) {
	if m.init {
		return nil, errors.New("mux client already used")
	}
	m.init = true
	m.singleResp = true

			if _, err := r.Open(f.Name); err != nil {
				continue
			}
		}

		// If we were unable to read anything out of the archive don't
		// bother trying to roundtrip it.
		if len(files) == 0 {
			return
		}

		w := NewWriter(io.Discard)
		for _, f := range files {
			ww, err := w.CreateHeader(f.header)
			if err != nil {

    assertThat(array).isEqualTo(new byte[] {(byte) 2, (byte) 1});
    array[1] = (byte) 3;
    assertThat(list).containsExactly((byte) 2, (byte) 3).inOrder();
  }

  public void testAsList_toArray_roundTrip() {
    byte[] array = {(byte) 0, (byte) 1, (byte) 2};
    List<Byte> list = Bytes.asList(array);
    byte[] newArray = Bytes.toArray(list);

    // Make sure it returned a copy
    list.set(0, (byte) 4);

				continue
			}
			files = append(files, file{header: hdr, content: buf.Bytes()})
		}

		// If we were unable to read anything out of the archive don't
		// bother trying to roundtrip it.
		if len(files) == 0 {
			return
		}

		out := bytes.NewBuffer(nil)
		w := NewWriter(out)
		for _, f := range files {
			if err := w.WriteHeader(f.header); err != nil {

		}
	}
}

func doCrawl(url string) error {
	defer wg.Done()

	req, err := http.NewRequest("GET", url, nil)
	if err != nil {
		return err
	}
	res, err := http.DefaultTransport.RoundTrip(req)
	if err != nil {
		return err
	}
	// Handle redirects.
	if res.StatusCode/100 == 3 {
		newURL, err := res.Location()
		if err != nil {
			return fmt.Errorf("resolving redirect: %v", err)
		}

    assertThat(array).isEqualTo(new byte[] {(byte) 2, (byte) 1});
    array[1] = (byte) 3;
    assertThat(list).containsExactly((byte) 2, (byte) 3).inOrder();
  }

  public void testAsList_toArray_roundTrip() {
    byte[] array = {(byte) 0, (byte) 1, (byte) 2};
    List<Byte> list = Bytes.asList(array);
    byte[] newArray = Bytes.toArray(list);

    // Make sure it returned a copy
    list.set(0, (byte) 4);

}

// RoundTripper provides an interface for type roundtrip serialization.
type RoundTripper interface {
	msgp.Unmarshaler
	msgp.Marshaler
	msgp.Sizer

	comparable
}

// SingleHandler is a type safe handler for single roundtrip requests.
type SingleHandler[Req, Resp RoundTripper] struct {
	id            HandlerID
	sharedResp    bool