I'm using tribulant newsletter plugin to send out newsletters from my site, using your plugin and Sendgrid as the "infrastructure".
Sending is VERY slow, I figure this is because the newsletter is sending each email in a separate transaction (REST).
Is there any way to batch us the send? have WP-Sendgrid queue up the emails and send several in a single REST call to sendgrid?
I know the same question should be asked the newsletter plugin author, but since the plugin is "unaware" of sendgrid, this would be problematic for them.