Purpose of stats-writer and why doveadm try to open it to dump stats ?

[Jean-Daniel]

Hello,

I want to monitor dovecot stats, and so I have an exporter process that run with limited rights. 
The monitoring user has only access to /var/run/dovecot/stats-reader and it works fine.
Doveadm stats dump returns the list of all stats as expected.

But each time I run doveadm stats dump, it logs the following error:

Error: net_connect_unix(/var/run/dovecot/stats-writer) failed: Permission denied

So what is the purpose of the stats-writer socket, and why doveadm try to open it to simply dump stats ? 
Is it really something it needs and I should update my user permissions or is it a doveadm bug ?