Interceptors via Default Interface Methods

[Nikey646]

It would be nice to be able to modify a request, both before and after, via default interface methods.

To be precise, inheriting an interface that defines PreSend and PostSend, or a middleware like method, with a next function that send the request, and returns the response.

I'm not entirely sure how this would work with generic support, so it might not be possible, but would definitely be a nice addition.