Impl From<HeaderName> for String

[matthiasbeyer]

Same as #921 - maybe there's a good reason why this isn't implemented. If so, it is not documented.

😄

[caspervonb]

This one might need some discussion, while it is not the case right now (we migrated away from http::header due to casing issues) we do ultimately want to not have any allocations for known headers.

e.g the internal representation is more likely to be something ala:

#[derive(Debug, Clone, Eq, PartialEq, Hash)]
enum Repr<T = ByteString> {
    Standard(StandardHeader),
    Custom(T),
}

[matthiasbeyer]

In this case it might still be an idea to provide some to_string() implementation for users, if they want to go the extra step and allocate a String, won't it?

[caspervonb]

So implement Display? (And get blanket ToString implementation).

[matthiasbeyer]

I don't know. Is this something that can be shown to a user of an application (or a developer that does some network debugging or whatever)?

And can ByteString (not sure whether it would come from) implement Display as well?

Maybe AsRef<str> would be enough...

[caspervonb]

And can ByteString (not sure whether it would come from) implement Display as well?

It can, semantics are just a bit different (imho). Into implies clean conversion, where-as ToString implies "get there in some way".

Did fmt::Display over in #924 which provides ToString.

Don't think we should provide a blanket into string implementation for HeaderName at this time. Feel free to rebut me on this tho.

[matthiasbeyer]

Closing as superseded by #924

@caspervonb 👍 thanks!