Flutter - How to save Firestore Geopoint to Json (especially Algolia)

I am having trouble with saving Firestore Geopoint to Json file. In my flutter app, I save Geopoint like this.

 FirebaseFirestore.instance.collection('ZayyanProperties').get().then(
              (value) => value.docs.forEach(
                (element) {
                  var docRef = FirebaseFirestore.instance
                      .collection('ZayyanProperties')
                      .doc(element.id);

                  docRef.update({
                    'b18-geopoint': GeoPoint(16.00001, 96.00001)
                  }); 

The value of Geopoint is stored in Firestore database properly. Please see a screenshot of my Firestore database here

My problem is that when the Geopoint is saved to Algolia as Json, it’s not saved properly. In the Json file of Algolia, Firestore Geopoint is saved as

  "_geoloc": {
    "lat": 16.00001,
    "lng": 96.00001
  },

But, I think its supposed to be saved like this??

  "b18-geopoint": {
    "lat": 16.00001,
    "lng": 96.00001
  },

Please see screenshot of Algolia Json here

So, my question is how do I properly save Geopoint in Json??

Thank you in advance.
Best

Algolia requires geolocation data to be stored in a custom attribute called _geoloc in order to be able to calculate proximity geo search within the index. The integration is probably doing the attribute translation by default.