At the present moment it's hard to build any type of generic functionality on top of gRPC C# API. It would be great if we have ability to apply interceptors around generic call definitions (ideally for both client and server side). From what I've seen such API has been exposed for Java and Go platforms.

Example use case for such functionality (which was cause for us to set up this issue) would be ability to set and receive Zipkin trace headers along with all client/server calls.