I'd like to (somewhat) self-plug error-stack. It's a new error-handling library which lets you efficiently attach any arbitrary (thread-safe) data to the Err arm of a Result. And before you ask why we wrote yet another error library 
we've got the answers in this post which goes through some of the philosophy. It's gotten some really positive feedback already and we think it'll be really helpful to a lot of people!
(Also small shout-out, it's based on some of the really cool work being done in core with the Provider API)