title: Android Firebase Cloud Messaging(FCM): Will subscribeToTopic do automatic retries?
body: <p>To Subscribe to a topic in an android client we should call:</p>
  
  <pre><code>FirebaseMessaging.getInstance().subscribeToTopic("news");
  </code></pre>
  
  <p>I want to know what happens if the internet connection is not available at moment that this instruction is executed?</p>
  
  <p>Will google services automatically retry to do subscription when Internet connection become available or we developer should handle this case?</p>