title: Long polling vs server events in context of mobile device and data usage
body: <p>Trying to decide on which protocol to use in my Android application.
  Doing research I see that long polling is more resource-intensive on server side because of constant reconnects. But it happens every 2 minutes or so.</p>
  
  <p>With server events - connection happens once and events being constantly sent to client (Android) - hence data usage.</p>
  
  <p>I also read people having problems with server events on 3G networks, when networks switch, etc</p>
  
  <p>I also wonder if data usage will be any different between server events and long polling? With long polling every 2 minutes set of headers will be sent. But with server events - something on a wire every 3 seconds.</p>
  
  <p>Question is.. What Google themselves uses?</p>
  
  <blockquote>
    <p>An FCM implementation includes an app server that interacts with FCM
    via HTTP or XMPP protocol, and a client app. You can compose and send
    messages using the app server or the Notifications console.</p>
  </blockquote>
  
  <p>Ok, but what is <code>HTTP</code> protocol in this case?</p>