title: OnNewToken call two times?
body: <p>As per the documentationof onNewToken,</p>
  
  <blockquote>
    <p>Called when a new token for the default Firebase project is generated.This is invoked after app install when a token is first generated, and again if the token changes.</p>
  </blockquote>
  
  <p>Q1. Does this mean, it be get called 2 times???</p>
  
  <p>Q2. I wan to send updated token to the server. If answer of Q1 is yes, then how to check onNewToken is received due to token change so that I can send updated token to server?</p>