title: FCM Push notifications 1000 users limit at a time issue
body: <p>I am using FCM to send push notifications to all my android app users to tell them about new poetry and wallpapers/backgrounds added to server </p>
  
  <p>Its working is like this:
  When user install android app first time its device token is received on our server via rest API written in php on server side and we are sending push notifications to user as soon as new wallpaper is available done via their device tokens received on our server by getting these from database in array and passing that array to FCM CURL Call in php</p>
  
  <p>Our Issue:
  Limit reached can not be exceeded from 1000 tokens at a time</p>
  
  <p>Our tries to solve that:
  We are sending now with for loop of each 900 users at a time in php and calling CURL to FCM in php for each 900 users again and again.
  Now notification are being received on some device and some are missing.
  Tell me how can I reliably send notifications to all devices without any limit issue instantly?  </p>