It takes many seconds in
change to a different maildir.
The following message appears as the new maildir is being read:
Reading /…/Maildir/.…... 1780/6926 (25%)
This takes ages! And is a total waste of IO, as only the bottom of the mailbox is ever examined, so, there is absolutely no need to look at each message, which, frankly, defeats the whole purpose of the maildir format, where it's actually very cheap to skip messages compared to mbox, and very expensive to load all of them.
Is there a fix?