Laravel - Notifications - Customizing The Mailer

By default, the email notification will be sent using the default mailer defined in the config/mail.php configuration file. However, you may specify a different mailer at runtime by calling the mailer method when building your message:

     * Get the mail representation of the notification.
     * @param  mixed  $notifiable
     * @return \Illuminate\Notifications\Messages\MailMessage
    public function toMail($notifiable)
        return (new MailMessage)