Error::UnsupportedKeyType holds a String

[rukai]

Previously errors looked like: UnsupportedKeyType([114, 115, 97])
But with this PR they now look like: UnsupportedKeyType("rsa")

[Eugeny]

Thank you for your contribution @rukai , however russh aims to provide an unambiguous interface to the SSH protocol. Conditionally stringifying key_type here creates a situation where it's unclear whether a string was sent as-is or is a result of format!()

[rukai]

Some alternatives:

• format as escape characters with https://doc.rust-lang.org/std/ascii/fn.escape_default.html
• format as "string: {}" or "bytes: {}", depending on if its utf8 or not.
• have both a string and raw bytes UnsupportedKeyType { string: String, raw: Vec<u8> }

Would one of these work?
I'm sure we can find a solution where the error is both readable and unambiguous.

[Eugeny]

Making UnsupportedKeyType a struct variant would be fine by me :)

[rukai]

Alright, I rewrote the PR to have both a raw and string field in a struct variant.

[Eugeny]

LGTM! @all-contributors please add @rukai for code

[allcontributors]

@Eugeny

I've put up a pull request to add @rukai! 🎉