[Dovecot] Defer emails until the user is ready to deal with them (snooze button / bring-forward file / bring-up file for emails)

[Chris Laif]

Hi, I would like to add a feature to my email-client (Thunderbird)
which stops emails from showing up until a specific time (e.g. having
buttons for: show again this evening, tomorrow, next week, next month
...).

As far as I've learned this is not possible with IMAP:
- storing the 'do-not-show-until-time' within a custom header-field
requires down- and uploading of the whole email and therefore causes
problems especially with large emails
- IMAP keywords are limited are limited in quantity and can not be
compared with datetime functions

Any suggestions will be greatly appreciated!

Chris