Can `Conv` be marked as `Send`?

[ChocolateLoverRaj]

I want to to create a pam module that can optionally take in input. For example, something like this: Either Wait 10 seconds or type "faster" and press enter to unlock.

The real use case is to write a fingerprint module (separate from libfprint).

[anowell]

Fwiw, I don't currently use or maintain this crate. I might be able to merge a PR with a test case, but it's pretty low priority for me to more generally support, so I'd encourage forking.