Cannot see the markers second time.

[deligence]

I'm using this package to display maps on two consecutive pages.
when I open the mapview on first page I'm able to see the markers and then when I open the mapview on next page it also works fine but then when I get back to the first page again and open the mapview then it shows nothing all the markers are gone.
Video for reference

_mapView.show(
          new MapOptions(
            showMyLocationButton: true,
            showCompassButton: true,
            mapViewType: MapViewType.normal,
            showUserLocation: true,
            initialCameraPosition:
                new CameraPosition(new Location(_lat, _lang), 15.0),
            title:
                '_title',
          ),
          toolbarActions: [
            _buildToolBarActionsMaps(),
            ToolbarAction("X", 1),
          ],
        );
        List<Marker> markers = <Marker>[
          new Marker(
              "1",
              "Text",
              _lat,
              _lang,
              color: Theme.of(context).accentColor,
              markerIcon: new MarkerIcon('assets/marker.png',
                  height: 80.0, width: 80.0)),
        ];
         StreamSubscription sub = _mapView.onMapReady.listen((_) {
          // setState(() {
            _mapView.setMarkers(markers);
          // });
        });                                             
   compositeSubscription.add(sub);
      sub = _mapView.onToolbarAction.listen((id) {
        if (id == 1) {
          _mapView.dismiss();
          compositeSubscription.cancel();
        }
      });
      compositeSubscription.add(sub);

[nitneuq33000]

Perfect demo of my problem... :( please find a solution

[nitneuq33000]

I don't know if it's the same issue but when I press on back button of my android device to close map . tags are removed after re open the map