Manage the pool processes such that they die after a limited quantity of time, and pick up messages from the spool asynchronously.
Let a single worker process timeout itself
Set the signal as late as possible
Abstract the method to pickup messages from the spool, so that a new recurring Timer may pick up messages out of the spool
Test Plan: * Run messages through it
Reviewers: PyKolab Developers
Subscribers: PyKolab Developers
Differential Revision: https://git.kolab.org/D617