Why Kryonet sending Object take too much network space?

Question

I'm following a trivial sample official Kryonet page:

https://github.com/EsotericSoftware/kryonet

And in Server I only send an empty class object:

MyEmptyObject object = new MyEmptyObject();
server.sendToAllTCP(object);

But I'm worry about the size of the Object that is about 44 bytes when I've catched with Wireshark. That's really hurt the network bandwidth because I'm trying to use Kryonet to create a Server-client multiplayer game. Is there something wrong with my setup or Kryonet is not targeted to game.