Thanks for that explanation! I'm going to have to dive into Rc/Arc [0]. Reference counting built into the standard library is really interesting. Several years ago I wrote a Windows kernel minifilter and reference counting is used a lot by anything that interacts with the filter manager. RC was very helpful to ensure the minifilter didn't leak memory when it was unloaded.

[0]: https://doc.rust-lang.org/std/sync/struct.Arc.html