ls event-post! in the event loop concerned.  This is
done in the same thread as that in which the event loop runs so it
cannot of itself be throttled.  However it may contribute to the
number of accumulated unexecuted tasks in the event loop and therefore
contribute to the throttling of other threads by the loop.  See the
documentation on the make-event-loop procedure for further information
about that.
</p>
<p>This procedure should not throw any exceptions unless memory is
exhausted.
</p>
<p>This procedure