def register! name, namespace = @default_registration_namespace, &callback_proc
      @@registration_guard.synchronize do
        raise Errors::RegistrationConflictError if registered_in_namespace? name, namespace
        @registered_callbacks[namespace] ||= Hash.new
        @registered_callbacks[namespace][name] = callback_proc
      end
    end
def register! name, namespace = @default_registration_namespace, &callback_proc
      @@registration_guard.synchronize do
        raise Errors::RegistrationConflictError if registered_in_namespace? name, namespace
        @registered_callbacks[namespace] ||= Hash.new
        @registered_callbacks[namespace][name] = callback_proc
      end
    end
Create a new DynamicRegistrar::Registrar
 @param [ Symbol ] default_registration_namespace The default namespace in which to register callbacks. Should not be set to nil.
 Register a new callback procedure. This method is thread-safe.
 @param [ Symbol ] name The name of the callback to register
 @param [ Symbol ] namespace The namespace in which to register the callback