[Dovecot] Why dovecot is not multi-threaded?

[Ruben Alvarez]

Hi,

I'm looking for the most efficient OpenSource IMAP server
and I am told that Dovecot Server is a good solution.

Anyway, I have inspected the source code and I think Dovecot is not a
multi-threaded server, but a forked server. I am surprised about this
issue, because threads perfomance should be higher than creating a new
process for each connection....I suppose.

So, Could anybody tell me why Dovecot was not designed with
multi-threaded support?.
Perhaps, threads are not a good solution for Dovecot but I am very
interested in which are the reasons for this.

By the other hand, ¿do anybody know any multi-threaded OpenSource IMAP
server?. I would like test performance of Dovecot  server versus a
multi-threaded one.

Very thanks.