title: Group notifications with Expo
body: <p>I have a react native messaging app done with Expo. I got notifications to work, but the problem is that each message is a separate notification.</p>
  
  <p>I would like to group notifications sent by the same person. Currently, I have:</p>
  
  <pre><code>[Notification]
  John - Hey, how are you?
  
  [Notification]
  John - Long time no see!
  </code></pre>
  
  <p>and I would like them to merge as a single one when the second message is received, like this:</p>
  
  <pre><code>[Notification]
  John |
     Hey, how are you?
     Long time to see!
  </code></pre>
  
  <p>I might be missing something because I cannot find anyone else wondering about such a common functionality.</p>
  
  <p>The code I use to send notifications from my backend (python):</p>
  
  <pre><code>headers = {
              'Accept': 'application/json',
              'Accept-encoding': 'gzip, deflate',
              'Content-Type': 'application/json',
          }
  
  session.post(
      "https://exp.host/--/api/v2/push/send", 
      json = {
          "to": expo_token, 
          "title": username, 
          "body": message_content, 
      }, 
      headers=headers
  )
  </code></pre>