I have modified the code for SMTPSender so that it sends to all addresses for a given domain in one SMTP connection. To acheive this I changed the implementation of the method:
SMTPResult send(Mail message, MailAddress exclude)
RemoteDeliveryMDB now passes in the Mail and passes in all local addresses in the exclude array, so that all mails get sent in one call to SMTPSender. SMTPSender then splits up the valid addresses by domain and does multiple delivery to each of them.
I'm a bit confused about the branching stuff, if I commit them to HEAD only I think we will get conflicts when merging the branch into HEAD, but it isn't really is a bug fix for M1 per se. Be great if somebody could suggest what to do :-)
Doh!!! Wrong forum