This module is a versatile and extensible implementation of the SMTP protocol
and its different evolutions like ESMTP and LMTP. The event driven
object-oriented API makes easy to incorporate the SMTP protocol to your
programs.

Other SMTPd implementations don't support useful ESMTP extensions and the LMTP
protocol. Their interface design precludes adding them later. So I've decided
to rewrite a complete implementation with extensibility in mind.