[racket] the benefactor in THREAD-RESUME

(Sorry for the duplicate -- I sent from the wrong address the first
time.)

   Date: Sun, 7 Nov 2010 14:27:11 -0700
   From: Jay McCarthy <jay.mccarthy at gmail.com>

   Read:

   http://www.cs.utah.edu/plt/kill-safe/

I read that, and grepped through the code, and the Racket 5.0 sources.
Every use I found outside of some contrived test cases in Racket is of
the form

(thread-resume t (current-thread)).

I understand the semantics of (thread-resume t1 t2), where t2 is not
the current thread; the paper and documentation explain that.  What I
don't understand is why one would ever do it.