ns in the thread which calls event-loop-run!: that
procedure will block while there are events to be processed.  In most
programs the event loop will run in the main program thread, with
which the program began.  Many programs using event loops are entirely
single threaded.
</p>
<p>However, the event loop provided by this module does support multiple
threads.  Most of the event loop procedures in this module are thread
safe and may be called in any thread.  The thread safe procedures are
event-loop-run! (as