Add adds an Extension controller to the given manager using the given AddArgs.

ClusterToExtensionMapper returns a mapper that returns requests for Extensions whose referenced clusters have been modified.

DefaultPredicates returns the default predicates for an extension reconciler.

NewReconciler creates a new reconcile.Reconciler that reconciles Extension resources of Gardener's `extensions.gardener.cloud` API group.

FinalizerPrefix is the prefix name of the finalizer written by this controller.

AddArgs are arguments for adding an Extension resources controller to a manager.

Actuator acts upon Extension resources.