C# version of Daedalus Lib?

I've been looking for an opensource (MIT or equivalent) implementation of a 2D pathfinding library in C#.

It should be navmesh based and support varying agent sizes and most importantly a dynamic environment e.g. allow to add and remove obstacles without having to completely regenerate the navmesh afterwards. (local repair operations)

The closest match I found is an AS3 lib called Daedalus. Does anyone happen to know of a C# port or some equivalent lib? I'm thinking of porting it myself... but it seems more likely a solution is already out there and I just didn't find it.