Multi-file examples

Cargo has an examples feature for showing people how to use your package.By putting individual files inside of the top-level examples directory, youcan create multiple examples.

But what if your example is too big for a single file? Cargo supports addingsub-directories inside of examples, and looks for a main.rs inside ofthem to build the example. It looks like this:

my-package
 └──src
     └── lib.rs // code here
 └──examples 
     └── simple-example.rs // a single-file example
     └── complex-example
        └── helper.rs
        └── main.rs // a more complex example that also uses `helper` as a submodule