code: func FilterAction(methodRef interface{}) FilterConfigurator {
  	var (
  		methodValue = reflect.ValueOf(methodRef)
  		methodType  = methodValue.Type()
  	)
  	if methodType.Kind() != reflect.Func || methodType.NumIn() == 0 {
  		panic("Expecting a controller method reference (e.g. Controller.Action), got a " +
  			methodType.String())
  	}
  
  	controllerType := methodType.In(0)
  	method := FindMethod(controllerType, methodValue)
  	if method == nil {
  		panic("Action not found on controller " + controllerType.Name())
  	}
  
  	for controllerType.Kind() == reflect.Ptr {
  		controllerType = controllerType.Elem()
  	}
  
  	return newFilterConfigurator(controllerType.Name(), method.Name)
  }
docs: // FilterAction returns a configurator for the filters applied to the given
  // controller method. For example:
  //   FilterAction(MyController.MyAction)