title: Can I add extra property to a MultiUserChat RoomInfo?
body: <p>In Smack, we can get the information of a room by RoomInfo. And now I have an extra info(like the location where a room belongs) for a room, how can I do this by smack?</p>
  
  <p>for example, in current smack:</p>
  
  <ul>
  <li>a admin can set room info(like description of a room) via
  <code>MultiUserChat.sendConfigurationForm(...);</code></li>
  <li>and a member can get info(like description of a room) via
  <code>MultiUserChat.getRoomInfo(...);</code></li>
  </ul>