Problem:

Related to #2764

s2n-quic-events isn't currently being published to crates.io, since it's only used internally by s2n-quic. s2n-tls will need to take a dependency on s2n-quic-events in order to implement its events system generation script, though. We'll need to refactor s2n-quic-events into a library that exposes functionality to generate an events system.

Before publishing the crate, we should also consider renaming it to something more generic like s2n-events.