Exec'ing a script from Cyrus when imapd has a client

[Xavier Bestel]

Hi,

I have a small install with cyrus-imapd 2.3.14, which reads some of its
mails with fetchmail. To limit the delay in mail delivery, fetchmail
awakes each minute to get mails.
What I would like is let fetchmail do that only when there's a client
actually reading its mails, i.e. an MUA actually connected to imapd.

So, my question: how to hook a script each time a client
connects/disconnects from imapd ?

Thanks,
	Xav