startRotation method
Starts the rotation of the globe.
Example usage:
FlutterEarthGlobeController controller = FlutterEarthGlobeController();
controller.startRotation();
Implementation
void startRotation({double? rotationSpeed}) {
_isRotating = true;
this.rotationSpeed = rotationSpeed ?? this.rotationSpeed;
rotationController.forward();
notifyListeners();
}