<td class="paramname">sendbufsz</td><td>The size of <code>sendbuf</code> in bytes. </td></tr>
    <tr><td class="paramdir">[in]</td><td class="paramname">recvbuf</td><td>A buffer that will be used for receiving messages from the broker. </td></tr>
    <tr><td class="paramdir">[in]</td><td class="paramname">recvbufsz</td><td>The size of <code>recvbuf</code> in bytes. </td></tr>
    <tr><td class="paramdir">[in]</td><td class="paramname">publish_response_callback</td><td>The callback to call whenever applicat