dispose method

Implementation

void dispose() {
  _positionSubject.close();
  _manualMoveSubject.close();
  _tapSubject.close();
  _longTapSubject.close();
  _doubleTapSubject.close();
  _dragNdropSubject.close();
  renderer.dispose();
  rotationNotifier.dispose();
  for (var datastore in List.of(_datastores)) {
    datastore.dispose();
  }
  _datastores.clear();
}