So if you're using #Rollbar and you use `deliver_now` and then try to capture any errors with a `rescue`, you'lll discover that... well... They still get reported to Rollbar!
Turns out, Rollbar automatically instruments `ActionMailer::MailDeliveryJob` and `deliver_now` uses `ActionMailer::MailDeliveryJob` under the covers, even tho the mail is being delivered synchronously!
Anyway, that particular "gotcha!" cost us about 80 engineering hours. Should we have given up sooner? Probably...