The D-Link DUB-E250 USB-C to 2.5G Ethernet Adapter allows the user to connect via USB-C to RJ45 2.5 Gigabit LAN. D-link notes this is compatible with Thunderbolt 3, Mac OS and Windows.
Description from Amazon:
The DUB-E250 USB-C to 2.5G Ethernet Adapter allows you to instantly add lightning-fast multi-gigabit wired connectivity to your ultraportable laptop computer or desktop. Just plug the DUB-E250 into an available USB Type-C or Thunderbolt 3 port, and you`re ready to connect to your router or switch with the speed and reliability of a wired connection. Installation is quick and easy with the pre-loaded software. For extra convenience, the adapter`s compact design means you can easily slip the DUB-E250 into your pocket or laptop bag and take it with you.