I had an old one lying around worked fine and it is from 5 years ago.
Also keep in mind that for now the usb 3.0 port on the switch is only 2.0 So no speed increase will be seen from A 3.0 Ethernet adapter atm.
Not saying buy a 2.0 adapter just if you happen to have a 2.0 lying around atm there is no reason to upgrade just yet.
5Ghz wifi is faster atm, but ethernet is always more reliable.