protected function buildMessage($mailMessage, $notifiable, $notification, $message)
    {
        $this->addressMessage($mailMessage, $notifiable, $notification, $message);

        $mailMessage->subject($message->subject ?: Str::title(
            Str::snake(class_basename($notification), ' ')
        ));

        $this->addAttachments($mailMessage, $message);

        if (! is_null($message->priority)) {
            $mailMessage->setPriority($message->priority);
        }
    }