title: Firebase push notification with data message or notification message
body: <p>I want to send a push notification to the user which does two things:</p>
  
  <ul>
  <li>inform the user a new file is available</li>
  <li>automatically download the file in the background so that it is available when the user opens the app</li>
  </ul>
  
  <p>For the first use case I can use a Notification Message and for the second a Data Message. But what is the best approach to combine both use cases?</p>
  
  <p>Idea 1:
  I could send two different messages for each use case?</p>
  
  <p>Idea 2:
  I use a Data Message and when the app receives the message the app takes care of showing a notification.</p>
  
  <p>Which one should I prefer or is there a better approach?</p>