title: ip address change notifications
body: <p>I'm using the Reachability class to detect wifi availability. </p>
  
  <p>There are some situations when an ipad will be connected to one wifi network,and a user will connect to another available wifi network.</p>
  
  <p>During these network transitions  reachable->unreachable->reachable notifications are not generated.</p>
  
  <p>This connection change where the ip address of the ipad changes is what Im trying to listen for. </p>
  
  <p>Do notifications for local wifi connection changes exist or will I have to just poll my ip periodically?</p>