libp2p (libp2p.io) networking for Unity C# projects
It's really, really rough. Well, early. I'm doing WEBGL targets (compiled to WASM/browser) first partly because browsers are so constrained network-wise: only able to use Websockets and/or WebRTC and not really able to listen for a connection at all. Mostly, though, it's because I already know how to have Unity C# code talk to browser-based Javascript and have already done so with a browserfied version of the Javascript version of libp2p.
Libp2p-Unity is a Unity 3D package allowing Unity apps written in C# to make use of the libp2p peer-to-peer networking stack for app-level communication.
The impetus for doing this is to be able to use libp2p as one of the available carrier network layers for apps using the Apian Framework, which really means creating a libp2p implementation of Apian's P2pNet networking API. It also implies that the main focus will be to make use of the libp2p.pubsub facility in doing so.
At the same time, however, it seemed like the vast majority of the work was going to be to get things to where C# Unity apps were able to talk to libp2p at all, and that once that worked the P2pNet pubsub implementation would be pretty easy (that is kinda the point to P2pNet.)
Libp2p-Unity is the result: It will be the basis for P2pNet.libp2p, but hopefully will also to be useful to folks who have no interest in Apian or P2pNet, and just want a way to use libp2p in their apps.
Note that I do not intend to make the entire set of libp2p capabilities available.
Given that there are already 3 different versions of libp2p (Go, Javascript, Rust) being maintained, it might seem like the best way to do this would be just to write a C# port. For me that's just a non-starter. libp2p is huge, with a whole pile of moving parts, and still really in development. What I really want to do with it for Apian, on the other hand, is pretty specific and will use a limited set of those parts.
So instead, I am going to make use of of the Foreign Function Interface capabilities present in C# and the languages that already have libp2p ports. It is demonstrably possible to use a compiled and browserfied version of js-libp2p for this when building for the browser. I expect that It'll be possible to do something similar for native build using libraries built from the Go and/or Rust versions.