A custom route loader allows you to add routes to an application without

including them, for example, in a YAML file. This comes in handy when

you have a bundle but don't want to manually add the routes for the bundle

to ``app/config/routing.yml``. This may be especially important when you want

to make the bundle reusable, or when you have open-sourced it as this would

slow down the installation process and make it error-prone.

Alternatively, you could also use a custom route loader when you want your

routes to be automatically generated or located based on some convention or

pattern. One example is the `FOSRestBundle`_ where routing is generated based

on the names of the action methods in a controller.