protected override void OnSaveInstanceState(Android.OS.Bundle outState)
 {
     base.OnSaveInstanceState(outState);
     outState.PutSerializable("dataset", mDataset);
     outState.PutSerializable("renderer", mRenderer);
     outState.PutSerializable("current_series", mCurrentSeries);
     outState.PutSerializable("current_renderer", mCurrentRenderer);
 }