Django backend could return wrong number of sent messages

[Stranger6667]

In case if some messages were bounced, and were not sent backend anyway will return total number of messages, that were passed to send_messages.

The problem is, that postmark will not rise any exceptions if batch send will be used. Thus, I see the following options:

• Use emails.send if email_messages contains only single email and emails.send_batch otherwise
• Add special setting to control this behaviour explicitly

And any way count only successfully sent messages.