Why Cargo Exists

Cargo is a tool that allows Rust packages to declare their variousdependencies and ensure that you’ll always get a repeatable build.

To accomplish this goal, Cargo does four things:

• Introduces two metadata files with various bits of package information.
• Fetches and builds your package’s dependencies.
• Invokes rustc or another build tool with the correct parameters to buildyour package.
• Introduces conventions to make working with Rust packages easier.