Internal errors might be reported to clients

[mrd0ll4r]

This was the case for the redis storage implementation, and it's probably also true for anything else on the announce path that can produce errors. I think we should come up with something to mark an error as "client-safe" to avoid exposing our internals...

[jzelinskie]

This is exactly what ClientError does?

[mrd0ll4r]

That's weird 🤔 I could have sworn I saw storage-internal errors on the client.. will investigate.