Подключить библиотеку к Delphi
https://github.com/zerotier/libzt
Официалы ответили:
libzt exposes a C API you would need to write an interface of some sort in your Delphi code to use libzt. We will not be offering any official support for a niche language like that so your best bet is to write your own wrapper and post tickets to GitHub if you get stuck.