handleMessage method
Implementation
@override
void handleMessage(
MapViewController mapViewController, Map<String, dynamic> payload) {
// Forward Viewer navigation events to the existing SDK callbacks.
// This avoids introducing a separate set of callbacks for the Viewer.
//
// Warning: running SDK and MapView navigations at the same time may mix
// events because both use the same public SDK navigation callbacks.
SitumSdk().updateNavigationState(payload);
}