How to register middlewares in OctoberCMS plugin?

Registering middlewares in Laravel is easy:

simply list the middleware class in the $middleware property of your app/Http/Kernel.php class

or

If you would like to assign middleware to specific routes, you should first assign the middleware a short-hand key in your app/Http/Kernel.php file

But how can this be done in an OctoberCMS plugin? Is the "Routing and initialization" meant to be used in place of Kernel.php to register middlewares? If not, where can a plugin register its own middlewares?

via Chebli Mohamed