not confirmed.
$mailer property($app['log']/$app['queue']/$mailer->alwaysFrom/$mailer->pretend($pretend))

Illuminate\Mail\MailServiceProvider::register()-------
   $mailer->setLogger($app['log'])->setQueue($app['queue']);
   $mailer->setContainer($app);
   // If a "from" address is set, we will set it on the mailer so that all mail
   // messages sent by the applications will utilize the same "from" address
   // on each one, which makes the developer's life a lot more convenient.
   $from = $app['config']['mail.from'];

   if (is_array($from) && isset($from['address']))
   {
    $mailer->alwaysFrom($from['address'], $from['name']);
   }

   // Here we will determine if the mailer should be in "pretend" mode for this
   // environment, which will simply write out e-mail to the logs instead of
   // sending it over the web, which is useful for local dev environments.
   $pretend = $app['config']->get('mail.pretend', false);

   $mailer->pretend($pretend);
----------------------------