Neat! Does this framework have any tools for content negotiation? I get that you could do this in the handlers themselves, but in my experience different representations are often so different in implementation that aside from maybe a tiny bit of shared code to produce some underlying dataset, the actual rendering of that data shares very little.

As an example: `application/json` and `text/html` respresentations of a single resource may render some of the same bits of data, but the actual rendering process is entirely different. Even if the content type is the same, you may render completely different output based on other parameters, like a header used to select between different profiles of said content type, or even just something simple as `accept-language`.

If it's not possible right now, is there any plans to support routing based not just on method and URL, but on headers as well?