 is fired when the library needs to read or write transferred data.<br>
&nbsp; ( Event procedures must be declared as a method of another object. )
<li>The <b>filename</b>, <b>stream</b>, <b>callback</b>, and <b>event</b> each have an
effect on the other, so they might not behave the way you expect!
</ul>
<br>
Please consider the following principles:
<p>
If you assign a <b>stream</b>, the <b>filename</b> will be ignored.<br>
If you assign a <b>filename</b>, the <b>stream</b> will be ignored.<br>
<br>
If yo