title: Background service to detect network status in Xamarin.Android
body: <p>I am developing Xamarin.Android app.
  In my app , I want to implement a background service  , which will run indefinitely to detect changes in network status.
  i.e. if network connection goes off , it should send such notification .
  It should send notification too when network connection becomes on(device got a network connection).
  Can anyone tell me how to implement such service in Xamarin.Android ?</p>