code: public function throwAt($timing, $method, $exception = false, $args = false)
      {
          $this->dieOnNoMethod($method, 'throw at');
          $this->actions->registerAt($timing, $method, $args,
                  new SimpleThrower($exception ? $exception : new Exception()));
      }
docs: Sets up a trigger to throw an exception upon the method call.
  
  @param int $timing        When to throw the exception. A value of 0 throws immediately.
  A value of 1 actually allows one call to this method before
  throwing. 2 will allow two calls before throwing and so on.
  @param string $method     Method name to throw on.
  @param object $exception  Exception object to throw.
  If not given then a simple Exception object is thrown.
  @param array $args        Optional argument list filter.
  If given then the exception will only be thrown
  if the method call matches the arguments.