private void onStateChange(IntPtr sourceGroup, IntPtr topWeightSource, IntPtr closure) { int mKey = closure.ToInt32(); Cookie cookie = mRegistrations[mKey] as Cookie; if (cookie != null && cookie.Key != 0) { MamaSourceStateChangeCallback mCallback = cookie.SourceStateChangeCallback; if (mCallback != null) { mCallback.onStateChanged(this, new MamaSource(topWeightSource)); } } }