o; and &rsquo;resume&rsquo; arguments).  The watch is multi-shot - it is
for the user to bring it to an end at the right time by calling
event-loop-remove-read-watch! in the waitable procedure.  If &rsquo;file&rsquo; is
a buffered port, buffering will be taken into account in indicating
whether a read can be made without blocking (but on a buffered port,
for efficiency purposes each read operation in response to this watch
should usually exhaust the buffer by calling drain-input or by looping
on char-ready?