[Twisted-Python] threadable.init() operation

[Clark C. Evans]

I've read the threading/enterprise howtos and am still
trying to grok thread <-> event loop communication.  In
particular, I'm curious what exactly what threadable.init()
does.  I was expecting something rather simple, which 
implementes communcation between the main event pump and
each thread (callInThread, callFromThread).  However, this
code seems to be doing much more than that, and I don't
quite understand what it is doing or why.  A bit of a 
primer would be great.

I'm asking this question beacuse adbapi isn't quite what
I need and before I go hacking around I was trying to get
a firmer grip on thread <-> event loop communication.

Best,

Clark