You may or may not know I was also involved in creating a few multi-player modification projects for games, namely the game called
Mafia: The City of Lost Heaven.
In mid-2013, we poked into the game's memory. We started figuring out how to sync the game's data and what methods to call (the addresses of which had to be found via a reverse engineering process). Eventually, we ended up with a scriptable server multi-player with the ability to stream modified client files.
Over time I'd contribute to numerous projects and eventually co-kickstart new ones. During that process, a new library was born that would help us streamline data/world streaming. We called it #librg!
The original name was ReGuider Framework, and it would do a little bit more than stream data back then. It somewhat substituted the need for a multi-player skeleton as it provided numerous features like scripting packages, networking, and entity management, ...
Over time we've reduced not only the name but the feature set itself, and nowadays, librg does not even offer any networking (although it's effortless to integrate one, see this enet demo).
Instead, #librg offers a stable, fast and reliable world chunk entity streaming with all the fancy utilities you need to sync your players in big worlds.