Lidgren.Network is a networking library for .NET, which uses a single UDP socket to deliver a simple API for connecting a client to a server, reading and sending messages. It supports .NET Framework 4.5+ and .NET Standard 2.0+. It should also work in Unity.
Space Wizards Edition is a maintained fork of Lidgren.Network with improvements such as bugfixes, performance improvements (Span<T>!), new features, etc...
If you'd like to get in contact with us or have any questions, you can ask in the development channel on our Discord. Also IRC: irc.rizon.net#spacebus (warning: IRC relay perhaps not 100% reliable, nobody uses it)