如何将坐标数组作为GeoPoint数据类型写入Cloud Firestore ？

我确实有一个arraylist<latlng> pointswith坐标，我需要将这些坐标写入Firestore：

@Override
public void onLocationChanged(Location location) {
    mLastLocation = location;

    mLatLng = new 
LatLng(location.getLatitude(),location.getLongitude());
    mMap.moveCamera(CameraUpdateFactory.newLatLng(mLatLng));

    mMap.animateCamera(CameraUpdateFactory.zoomTo(20));

    if (mDraw) {
        points.add(mLatLng); //added
        drawPolyLine();
    }


}

private void drawPolyLine(){
    mMap.clear();

    PolylineOptions options = new 
PolylineOptions().width(5).color(Color.BLUE).geodesic(true);
    for (int i = 0; i < points.size(); i++) {
        LatLng point = points.get(i);
        options.add(point);
    }

    line = mMap.addPolyline(options); //add Polyline
}

我试着docRef.update("Test", FieldValue.arrayUnion(points));和docRef.set(points);都导致错误Nested arrays not supported和required map String or related POJO respectively。