title: Can anyone explain to me about "volatile" message in socket.io/nodejs?
body: <p>In new socket.io v0.7, there's a new feature "volatile message".</p>
  
  <p>In "how to use", they write like that:(at <a href="http://socket.io/#how-to-use">http://socket.io/#how-to-use</a>)</p>
  
  <blockquote>
    <p>Sending volatile messages.</p>
    
    <p>Sometimes certain messages can be dropped. Let's say you have an app that shows realtime >tweets for the keyword <code>bieber</code>.</p>
    
    <p>If a certain client is not ready to receive messages (because of network slowness or other >issues, or because he's connected through long polling and is in the middle of a request- >response cycle), if he doesn't receive ALL the tweets related to bieber your application >won't suffer.</p>
    
    <p>In that case, you might want to send those messages as volatile messages.</p>
  </blockquote>
  
  <p>As I think volatile is something like inconsistent so why they told that we should use volatile message for the type of message we mustn't missed? What about default messages? What must I do to be sure the message will arrive to client?</p>
  
  <p>Beside, I also want to ask about xhr-multipart transport. I don't see it in list of transport in v0.7. Was it removed?</p>