Feature Request: OpenAPI integration

Hi there,

First of all thanks for this interesting lib. Particularly the README.md was very helpful and made me interested further in reading some of the code.

I know the tool already provides quite a bit functionality however one thing that I had as a epiphany lately is that, the next gen http servers APIs will be self-documenting, as in it can/will generate openAPI spec with very little to no input from the developer. Thus I think this feature is almost a necessity in terms of priority. What do you think?

Thanks again for all the work, I'm now following this repo ;)