This is my code as I go through the online book,
The Rust Programming Language
It's broken down by chapter numbers, which might change since the online book may get updated at any point.
It's nicer to just have a single VSCode window open at the root of the repo, AKA a single VSCode workspace that contains all the rust binary projects. The root of the repo contains a Cargo.toml, which defines a Cargo Workspace and references each project. If we don't have this, the rust-analyzer can't find the projects.