I want to send out batch mails using SwiftMail or any similar system. The SwiftMailer docs state that:
"Each recipient of the messages receives a different copy with only their own email address on the To: field. An integer is returned which includes the number of successful recipients."
http://swiftmailer.org/docs/batchsend-method
I want to know whether it's possible to find out which email addresses failed, and optionally obtain the error reason/code.