errFatal(local.RegisterSingleHandler(handlerTest, func(payload []byte) ([]byte, *RemoteErr) {
		t.Log("1: server payload: ", len(payload), "bytes.")
		return append([]byte{}, payload...), nil
	}))
	// 2: Return as error
	errFatal(local.RegisterSingleHandler(handlerTest2, func(payload []byte) ([]byte, *RemoteErr) {
		t.Log("2: server payload: ", len(payload), "bytes.")
		err := RemoteErr(payload)
		return nil, &err
	}))

	remote := grid.Managers[1]

func NewRemoteErrString(msg string) *RemoteErr {
	r := RemoteErr(msg)
	return &r
}

func (r RemoteErr) Error() string {
	return string(r)
}

// Is returns if the string representation matches.
func (r *RemoteErr) Is(other error) bool {
	if r == nil || other == nil {
		return r == other
	}
	var o RemoteErr
	if errors.As(other, &o) {
		return r == &o
	}

	defer p.Recycle()
	return s.RenameDataHandler(&p.RenameDataHandlerParams)
}

// RenameFileHandler - rename a file from source to destination
func (s *storageRESTServer) RenameFileHandler(p *RenameFileHandlerParams) (grid.NoPayload, *grid.RemoteErr) {
	if !s.checkID(p.DiskID) {
		return grid.NewNPErr(errDiskNotFound)
	}

		// Register a single handler which echos the payload.
		errFatal(remote.RegisterSingleHandler(handlerTest, func(payload []byte) ([]byte, *RemoteErr) {
			defer PutByteBuffer(payload)
			return append(GetByteBuffer()[:0], payload...), nil
		}))
		errFatal(rpc.Register(remote, func(req *testRequest) (resp *testResponse, err *RemoteErr) {
			return &testResponse{
				OrgNum:    req.Num,
				OrgString: req.String,
				Embedded:  *req,
			}, nil
		}))

	if v, ok := c.outgoing.Load(m.MuxID); ok {
		var cErr muxConnectError
		_, err := cErr.UnmarshalMsg(m.Payload)
		gridLogIf(ctx, err)
		v.error(RemoteErr(cErr.Error))
		return
	}
	PutByteBuffer(m.Payload)
}

func (c *Connection) handleAckMux(ctx context.Context, m message) {
	PutByteBuffer(m.Payload)
	v, ok := c.outgoing.Load(m.MuxID)

}

// WalkDirHandler - remote caller to list files and folders in a requested directory path.
func (s *storageRESTServer) WalkDirHandler(ctx context.Context, payload []byte, _ <-chan []byte, out chan<- []byte) (gerr *grid.RemoteErr) {
	var opts WalkDirOptions
	_, err := opts.UnmarshalMsg(payload)
	if err != nil {
		return grid.NewRemoteErr(err)
	}

	if !s.checkID(opts.DiskID) {
		return grid.NewRemoteErr(errDiskNotFound)
	}

	ok := m.addResponse(r)
	if !ok {
		PutByteBuffer(r.Msg)
	}
}

var errStreamEOF = errors.New("stream EOF")

// error is a message from the server to disconnect.
func (m *muxClient) error(err RemoteErr) {
	if debugPrint {
		fmt.Printf("mux %d: got remote err:%v\n", m.MuxID, string(err))
	}
	m.addResponse(Response{Err: &err})
}

func (m *muxClient) ack(seq uint32) {
	if !m.checkSeq(seq) {
		return