Pretty sure most applications don't need to support RFC 2177 to still be efficient. Long-polling for most IMAP servers requires one packet every nine minutes (to the best of my knowledge), which is literally nothing. It would take months of being run constantly to even get up to a megabyte of data being transferred. Some rough back of the envelope calculations:

- 10 minutes per poll, 1440 minutes in a day, 144 packets per day.

- 50 bytes per packet, 1,000,000 bytes to a megabyte, 20,000 packets required.

- Roughly 140 days of time, or 5 months to reach a single megabyte.

Aren't there some optimisations that are so minuscule it isn't worth implementing them?