title: Firebase messaging app/network-timeout from firebase functions
body: <p>my push notification code from the firebase function looks like below:</p>
  
  <pre><code> //fetch push tokens of all admins as well to send push notification
          var tokens = []
  
          if(pushToken !== undefined &amp;&amp; pushToken !== '')
              tokens.push(pushToken)
  
          tokens = tokens.concat(adminPushTokens)
  
  
          //push tokens need to be of customer as well as all the admins in the system. fetch admin push tokens
          admin.messaging().sendToDevice(tokens, pushPayload).then(
              (resp) =&gt; console.log("push notification sent")
          ).catch(
              (err) =&gt; console.error("Error sending push notification:" + JSON.stringify(err))
          )
  </code></pre>
  
  <p>And for 15-20% of the time it ends up in </p>
  
  <pre><code> Error sending push notification:{"code":"app/network-timeout","message":"fcm.googleapis.com network timeout. Please try again."}
  </code></pre>
  
  <p>This is a big issue for us and not an acceptable performance. How can we make sure to improve the reliability?</p>