Fix allow_unknown_extensions = true

[pacman82]

Hello Dear Maintainers,

thanks for this crate. I like it a lot. I already use it in a pet project of mine. I can not yet use it in my dayjob though. Responsible is this bug:

allow_unknown_extensions = true currently sets all content-type headers to application/octet-stream. Even if their mime type is known.

This PR provides a reproducing test and a fix.

Best, Markus

[ThinkerDreamer]

Great catch, @pacman82! The bug is ok_or() vs ok_or_else(). The original should have used ok_or_else() since https://doc.rust-lang.org/std/option/enum.Option.html#method.ok_or says:

Arguments passed to ok_or are eagerly evaluated; if you are passing the result of a function call, it is recommended to use ok_or_else, which is lazily evaluated.

Thanks!

[paolobarbolini]

Released as v0.6.1
https://crates.io/crates/static-serve/0.6.1

[pacman82]

Thanks!