Cargo workspaces for multi-package projects

Cargo used to have two levels of organization:

• A package contains one or more crates
• A crate has one or more modules

Cargo now has an additional level:

• A workspace contains one or more packages

This can be useful for larger projects. For example, the futures packageis a workspace that contains many related packages:

• futures
• futures-util
• futures-io
• futures-channel

and more.

Workspaces allow these packages to be developed individually, but they sharea single set of dependencies, and therefore have a single target directoryand a single Cargo.lock.

For more details about workspaces, please see the Cargo documentation.