func (s *peerRESTServer) LoadPolicyMappingHandler(mss *grid.MSS) (np grid.NoPayload, nerr *grid.RemoteErr) {
	objAPI := newObjectLayerFn()
	if objAPI == nil {
		return np, grid.NewRemoteErr(errServerNotInitialized)
	}
	userOrGroup := mss.Get(peerRESTUserOrGroup)
	if userOrGroup == "" {
		return np, grid.NewRemoteErr(errors.New("user-or-group is missing"))
	}

	userType, err := strconv.Atoi(mss.Get(peerRESTUserType))
	if err != nil {

		t.Errorf("%d bytes left over after Skip(): %q", len(left), left)
	}
	if !reflect.DeepEqual(v, v2) {
		t.Errorf("MSS: %v != %v", v, v2)
	}
}

func TestMarshalUnmarshalMSSNil(t *testing.T) {
	v := MSS(nil)
	bts, err := v.MarshalMsg(nil)
	if err != nil {
		t.Fatal(err)
	}
	v2 := MSS(make(map[string]string, 1))
	left, err := v2.UnmarshalMsg(bts)
	if err != nil {
		t.Fatal(err)
	}
	if len(left) != 0 {

type Recycler interface {
	Recycle()
}

// MSS is a map[string]string that can be serialized.
// It is not very efficient, but it is only used for easy parameter passing.
type MSS map[string]string

// Get returns the value for the given key.
func (m *MSS) Get(key string) string {
	if m == nil {
		return ""
	}
	return (*m)[key]
}

// Set a key, value pair.
func (m *MSS) Set(key, value string) {
	if m == nil {

        final MavenSession ms = requireNonNull(t);
        final MavenSession mss;
        if (repoSession != ms.getRepositorySession()) {
            mss = new MavenSession(repoSession, ms.getRequest(), ms.getResult());
        } else {
            mss = ms;
        }
        return newSession(mss, repositories);
    }

	if conn == nil {
		return madmin.HealResultItem{}, nil
	}

	mss := grid.NewMSSWith(map[string]string{
		peerS3Bucket:        bucket,
		peerS3BucketDeleted: strconv.FormatBool(opts.Remove),
	})

	ctx, cancel := context.WithTimeout(ctx, globalDriveConfig.GetMaxTimeout())
	defer cancel()

	resp, err := healBucketRPC.Call(ctx, conn, mss)
	return resp.ValueOrZero(), toStorageErr(err)
}

These must provide `msgp` serialization and deserialization.

In the examples we use a `MSS` type, which is a `map[string]string` that is `msgp` serializable.

```go
    handler := func(request *grid.MSS) (*grid.MSS, *grid.RemoteErr) {
        fmt.Println("Got request with field", request["myfield"])
        // Do something with payload

	// 1: Echo
	h1 := NewSingleHandler[*MSS, *MSS](handlerTest, NewMSS, NewMSS)
	// Handles incoming requests, returns a response
	handler1 := func(req *MSS) (resp *MSS, err *RemoteErr) {
		resp = h1.NewResponse()
		maps.Copy((*resp), *req)
		return resp, nil
	}
	// Return error
	h2 := NewSingleHandler[*MSS, *MSS](handlerTest2, NewMSS, NewMSS)
	handler2 := func(req *MSS) (resp *MSS, err *RemoteErr) {
		defer req.Recycle()

	storageReadVersionRPC      = grid.NewSingleHandler[*grid.MSS, *FileInfo](grid.HandlerReadVersion, grid.NewMSS, func() *FileInfo { return &FileInfo{} })
	storageReadXLRPC           = grid.NewSingleHandler[*grid.MSS, *RawFileInfo](grid.HandlerReadXL, grid.NewMSS, func() *RawFileInfo { return &RawFileInfo{} })

			return resp, nil
		}
		return resp, ErrDisconnected
	}
	payload, err := req.MarshalMsg(GetByteBufferCap(req.Msgsize()))
	if err != nil {
		return resp, err
	}
	switch any(req).(type) {
	case *MSS, *URLValues:
		ctx = context.WithValue(ctx, TraceParamsKey{}, req)
	case *NoPayload, *Bytes:
		// do not need to trace nopayload and bytes payload
	default: