A HeaderCollection Feature for pseudo headers

### Is there an existing issue for this?

- [x] I have searched the existing issues

### Is your feature request related to a problem? Please describe the problem.

When Kestrel or a server reads in a header that is unlikely to be needed by the "application" (here the actual endpoints/request delegates) itself, but only needed for routing, etc. then those headers don't need to be encoded to UTF-16.

### Describe the solution you'd like

I would like to have a feature for a "pseudo header collection" (HeaderCollection for pseudo headers: authority, method, path, etc.) that allows for getting and setting items in Latin1 or UTF-8 format. Then headers that are most likely never used by the endpoints directly don't need explicit UTF-16 decoding if the rest of ASP.NET Core can work with the given encoding.
When the default (Latin1) encoding is changed to something exotic, the feature could fall back encoding to UTF-8?

### Additional context

_No response_