).
</p>
<p>This procedure is mainly intended as something from which higher-level
asynchronous file operations can be constructed, such as the
await-readline! procedure.  The &rsquo;loop&rsquo; argument is optional: this
procedure operates on the event loop passed in as an argument, or if
none is passed (or #f is passed), on the default event loop
</p>
<p>Because this procedure takes a &rsquo;resume&rsquo; argument derived from the
a-sync procedure, it must (like the a-sync procedure) in practice be
called 