[firebase_messaging] setGroup in message JSON

[lironzemingo]

regarding the attached JSON - is there a way to set a group (in order to bundle messages) in JSON? I did not see that in the documentation.

await admin.messaging().send({
  token: 'YOUR_TOKEN_HERE',
  apns: {
    payload: {
      aps: {
        threadId: 'foo',
        alert: 'Hello world',
      },
    },
  },
  android: {
    collapseKey: 'foo',
    notification: {
      title: 'Hello world',
    },
  },
});