Possibly safe usage of Thread#raise?

I’ve rewritten and heavily commented the ThreadTimeout middleware of
Rainbows![1]. I believe it’s safe given the documented limitations (see
link), but would greatly appreciate code review from anybody willing and
able.

Original post to Rainbows! mailing list here[2]:
http://mid.gmane.org/[email protected]

Thread will/may be here (warning: frames):
http://thread.gmane.org/gmane.comp.lang.ruby.rainbows.general/222

Feel free to respond here or to the Rainbows! mailing list[2]

The Rainbows! mailing list doesn’t require subscription, just remember
to tell people to Cc: you if you’re not subscribed. The Message-ID
for the In-Reply-To: header is [email protected]

Thanks for reading!

[1] - http://rainbows.rubyforge.org/
[2] - [email protected] I don’t think many people are
subscribed, so I’m asking for help here since I suspect more
people pay attention to ruby-talk :slight_smile: