Add support for running actions during routing

[captainsafia]

As part of the recent work to add better form support for minimal APIs, we've needed to add logic in the endpoint routing middleware to ensure that certain metadata is able to configure HTTP features before other middlewares run. The routing middleware is convenient here because it is the earliest point wherein we can set these features before other middleware can run.

While form support and anti-forgery are strong motivating examples, the general model of being able to run "filters" during routing is helpful enough that we should consider provide a more generic API for this.

Thanks for contacting us.

We're moving this issue to the .NET 9 Planning milestone for future evaluation / consideration. We would like to keep this around to collect more feedback, which can help us with prioritizing this work. We will re-evaluate this issue, during our next planning meeting(s).
If we later determine, that the issue has no community involvement, or it's very rare and low-impact issue, we will close it - so that the team can focus on more important and high impact issues.
To learn more about what to expect next and how this issue will be handled you can read more about our triage process here.