- prefer https://lib.rs/ over crates.io
- borrowing and ownership are TWO DIFFERENT THINGS. changing ownership means "move"; borrowing is just temporary.
- lifetimes rarely needed.
- install using rustup.
- thinking using stack and heap is difficult sometimes.
- Suggest: start just with plain functions, then add objects into it.
- https://newrustacean.com/ is great, esp. https://newrustacean.com/show_notes/e005/index.html