Allow to clone a Identity

[silvioprog]

For example, it can be useful when we need to store an Identity in a hash map. (I'm facing exactly this problem in a small project I'm developing)

[silvioprog]

Hey guys, what do you think about this PR? Any questions/changes?! 🙂

[seanmonstar]

Seems find to me! The only concern would be if at some future point, we added support for a certificate type that couldn't be clone. Does that seem likely? That is probably why I didn't have that implementation in the first place, and I couldn't think of a time you'd want to construct an Identity and then clone it. I don't have a strong opinion. If you have thought about that point, I'd welcome hearing.

I'm fine merging as long we make sure to have thought about any potential consequences :)

[silvioprog]

Seems find to me! The only concern would be if at some future point, we added support for a certificate type that couldn't be clone. Does that seem likely? That is probably why I didn't have that implementation in the first place, and I couldn't think of a time you'd want to construct an Identity and then clone it. I don't have a strong opinion. If you have thought about that point, I'd welcome hearing.

I'm not sure if I'll help, but I'll comment based on my experience in the last companies I worked for. Many applications keep certificates in files or in a database. Depending on the certificate type, it demands a lot of processing to be loaded at run time, this way, we [pre]load it to a temporary list, in general, a hashed list using the user Unique Identifier as key and filled by demand. This is one of the reasons why a clonable Identity could help a lot. But there are many other situations that a clonable structure can help, even in situations with a single certificate file involved. For example, when the user needs to serve some web service through TLS authentication handled by a Warp filter or an Axum extension (I'm facing this second situation, but handling a lot of certificates).

I'm fine merging as long we make sure to have thought about any potential consequences :)

It would be really appreciated. I'm not so experienced with Rust, but a type that allows to be used inside lists is very required in many cases.

[silvioprog]

Thanks a lot for applying!