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]

The server handler function has this signature: `type SingleHandlerFn func(payload []byte) ([]byte, *RemoteErr)`.

Sample handler:
```go
    handler :=  func(payload []byte) ([]byte, *grid.RemoteErr) {
        // Do something with payload
        return []byte("response"), nil
    }

    err := manager.RegisterSingleHandler(grid.HandlerDiskInfo, handler)
```

		}
		PutByteBuffer(m.Payload)
		return
	}
	if m.Flags&FlagPayloadIsErr != 0 {
		v.response(m.Seq, Response{
			Msg: nil,
			Err: RemoteErr(m.Payload),
		})
		if v.cancelFn != nil {
			v.cancelFn(RemoteErr(m.Payload))
		}
		PutByteBuffer(m.Payload)
		v.close()
		c.outgoing.Delete(m.MuxID)
		return
	}
	// Return payload.
	if m.Payload != nil {