title: Firebase sending multiple push notifications instead of stacking or replacing
body: <p>I am trying to have a previous push notification stack with the new one or replace it in the system tray for android.</p>
  
  <p>I am not sure how to do this as the push notification is sending back both data and notification objects, and from what I understand the notification goes directly to the system tray. If so how do I stop the notification from appearing independently. Some users would get 5-10 notifications and it would keep pushing up.</p>
  
  <p>EDIT:</p>
  
  <p>I tried collapse_key but it still does not replace prior notifications with the same key... am I doing it wrong somehow here?</p>
  
  <pre><code>method: 'POST',
                              uri: 'https://gcm-http.googleapis.com/gcm/send',
                              headers: {
                                  'Content-Type': 'application/json',
                                  'Authorization': authorize //GOOGLE API KEY
                              },
  
                              body: JSON.stringify({
                                  "registration_ids": [otherUserResult.reg_id],
  
                                  "collapse_key": "follow",
                                  "data": {
                                      "notifyToUserId": to,
                                      "notifyFromId": from,
                                      "notifyMsg": msg,
                                      "notifyItemPicture": itemPic,
                                      "notifyItemName": itemName,
                                      "notifyFromName": fromName,
                                      "notifyType": type,
                                      "dateNotified": dateNotified
  
  
                                  },
                                  "notification": {
                                      "title": fromName,
                                      "body": notifyMsg,
                                      "icon"  : "ic_pushnotify"
                                  },
                                  "priority": "high",
                                  "content_available": true
  </code></pre>