 is intended to be called in a waitable procedure
invoked by a-sync, and this procedure is implemented using
await-glib-put-bytevector.
</p>
<p>For reasons of efficiency, this procedure by-passes the port&rsquo;s output
buffer (if any) and sends the output to the underlying file descriptor
directly.  This means that it is most convenient for use with
unbuffered ports.  However, this procedure can be used with a port
with buffered output, but if that is done and the port has previously
been used for output b