Arbor sends an e-mail every time a new message appears, but this e-mail is only a "you have mail" notification, it does not actually contain the message, or even a link to the message.
All these e-mails' bodies are identical
the From address is the same as the .env FROM_EMAIL
the time is the same (or similar) as the message's received time
Instead of polling, only download each message from the Arbor website in response to the notification e-mail appearing in the IMAP inbox.
Delete the notification once the message has been inserted into the IMAP inbox
this adds the benefit of, if something should go wrong with the program, having the notification message in the inbox; this way the user is at least alerted something went wrong
Arbor sends an e-mail every time a new message appears, but this e-mail is only a "you have mail" notification, it does not actually contain the message, or even a link to the message.