Builds the bundle.
It is only ever called once when the cache is empty.
This method can be overridden to register compilation passes, other extensions, ...
ContainerBuilder $container A ContainerBuilder instance:
Overrides Bundle::build
public function build(ContainerBuilder $container) {
$container
->register('bundle_test_class', 'Drupal\\bundle_test\\TestClass')
->addTag('event_subscriber');
// Override a default bundle used by core to a dummy class.
$container
->register('file.usage', 'Drupal\\bundle_test\\TestFileUsage');
}