initial commit

Attempted to setup a basic architecture that could work across frameworks and
formats.

Intended as a discussion starter!
Hmmm, not 100% sure. :)

I'm currently working on some export code for a consulting gig where we extensively use `TextWriter`. Also, if you look at the Json.NET specific converters (in f.ex. WebApi.HAL) they also append to a writer. Concluding, it just felt natural.

I do feel that a writer is more explicit than a stream, as consuming code cannot do any reading or other things to the `ResponseStream` (because that is what it is essentially).

It does make for simple unit/approval-testing imho.

Let me flip the question though, why use the `Stream` directly?