Optimize usage of clone()?

[smyrick]

          There's not; it's due to a lot of borrowing issues, but the [Rust book has a good description of why it's not necessarily a huge issue](https://rust-unofficial.github.io/patterns/anti_patterns/borrow_clone.html#:~:text=If%20a%20clone%20is%20used,is%20still%20new%20to%20ownership) for this project at the moment, and we can optimize later.

Originally posted by @lleadbet in #2 (comment)