The manager of services.
Gets the service provider for the service of the given clazz type, or returns null if there is no service provider for the given clazz.
Gets the provider for the given type T, or returns null if there is no provider for the given type T.
Gets the service for the given clazz, or returns null if there is no service registered for the given clazz.
Gets the service for the given type T, or returns null if there is no registered service for the given type T.
Registers a new service to this services manager.