C# KCP based on the original C kcp.

Works with netcore and Unity.

Developed for Mirror Networking.

Questions & support on Mirror Networking Discord.

• Kcp.cs based on kcp.c v1.7, line-by-line translation to C#
• Heavy test coverage
• Fixed WND_RCV bug from original kcp
• Optional high level C# code for client/server connection handling
• Optional high level Unreliable channel added

Pull requests for bug fixes & tests welcome.

kcp2k works perfectly with Unity, see the Mirror repository's KcpTransport.

The client is allocation free. The server's SendTo/ReceiveFrom still allocate.

Previously, where-allocation for a 25x reduction in server allocations. However:

• It only worked with Unity's old Mono version.
• It didn't work in Unity's IL2CPP builds, which are still faster than Mono + NonAlloc
• It didn't work in regular C# projects.
• Overall, the extra complexity is not worth it. Use IL2CPP instead.
• Microsoft is considering to remove the allocation.

• Congestion Control should be left disabled. It seems to be broken in KCP.