protected unsafe void EnableActionGetPositionInfo()
        {
            iCallbackGetPositionInfo = new CallbackGetPositionInfo(DoGetPositionInfo);
            IntPtr ptr = GCHandle.ToIntPtr(iGch);

            DvServiceUpnpOrgAVTransport2EnableActionGetPositionInfo(iHandle, iCallbackGetPositionInfo, ptr);
        }
 static extern void DvServiceUpnpOrgAVTransport2EnableActionGetPositionInfo(uint aHandle, CallbackGetPositionInfo aCallback, IntPtr aPtr);