<code>udp4</code> sockets) or <code>'::1'</code>
(for <code>udp6</code> sockets) will be used by default.</p>
<p>If the socket has not been previously bound with a call to <code>bind</code>, the socket
is assigned a random port number and is bound to the "all interfaces" address
(<code>'0.0.0.0'</code> for <code>udp4</code> sockets, <code>'::0'</code> for <code>udp6</code> sockets.)</p>
<p>An optional <code>callback</code> function may be specified to as a way of reporting
DNS errors or for determining when