Rust has a burgeoning async system. If your application is heavy on IO, you should simply “use async” and everything will work efficiently. You can have async fn, .await whenever that could be worked on in the background while the CPU does something useful. Then you learn to add Tokio for it to do anything and things may seem like magic. Fortunately, computers do not work by magic yet, so we can try to simplify things and get a better understanding. Today I want to do just that.