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

    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);

    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

    component[builder] = codePointString
    val url = builder.build()
    val expected = component.canonicalize(codePointString)
    val actual = component[url]
    if (expected != actual) {
      fail("Roundtrip $component $codePoint $url $expected != $actual")
    }
  }

  private fun testParseOriginal(
    codePoint: Int,
    codePointString: String,
    encoding: Encoding,
    component: Component,
  ) {

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

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

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

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

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

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