td class="paramname">client_id</td><td>The unique name identifying the client. </td></tr>
    <tr><td class="paramdir">[in]</td><td class="paramname">will_topic</td><td>The topic name of client's <code>will_message</code>. If no will message is desired set to <code>NULL</code>. </td></tr>
    <tr><td class="paramdir">[in]</td><td class="paramname">will_message</td><td>The application message (data) to be published in the event the client ungracefully disconnects. Set to <code>NULL</code> if <code>will_topic