or it could be used to provide a way to customize the protocol
to fit a particular (closed) network.</p>
<p>In short, the <a class="reference external" href="reference-Plugins.html#plugin">plugin</a> interface makes it possible to:</p>
<ul class="simple">
<li>register extension messages (sent in the extension handshake), see
<a class="reference external" href="manual-ref.html#extensions">extensions</a>.</li>
<li>add data and parse data from the extension handshake.</li>
<li>send extension messages and stand