[SignalR] Autobahn-like test suite for SignalR

### Is your feature request related to a problem? Please describe.
I started working on SignalR implementation for Rust, which I believe is missing. I want to have a way to verify if the implementation is correct and has all the required features.

### Describe the solution you'd like
I am looking for an automated test suite for SignalR much like the Autobahn test suite for WebSockets. Is there such a thing? I filed it as a feature request, but I am not sure if this is correct. After all, if it is missing or not public, it is a kind of feature request.

If I started the issue in the wrong place, please redirect me to the correct one.