C# with multiplayer over network using Timeline
Janus toolkit (http://dundee.cs.queensu.ca/wiki/index.php?title=Janus2) using LiteNetLib (https://github.com/RevenantX/LiteNetLib)
Read more about Janus here https://link.springer.com/article/10.1007/s00530-012-0271-3 Timelines: simplifying the programming of lag compensation for the next generation of networked games