protected function throwException(Swift_TransportException $e)
    {
        if ($evt = $this->eventDispatcher->createTransportExceptionEvent($this, $e)) {
            $this->eventDispatcher->dispatchEvent($evt, 'exceptionThrown');
            if (!$evt->bubbleCancelled()) {
                throw $e;
            }
        } else {
            throw $e;
        }
    }