Log Message:
Update to 1.4.20:

Overview

Just one tiny change to fix a regression causing threads to lock
up and spin max CPU.

1.4.18 and 1.4.19 were affected. 1.4.17 and earlier were not
affected. If you are on .18 or .19 an upgrade to 1.4.20 is strongly
advised.

Thanks to commando.io for reporting the bug initially and putting
up with me being blind for a few weeks.

Fixes

Fix a race condition causing new connections to appear closed,
causing an inifinte loop.