/**@name About Callbacks * * The Linux SDK for UPnP Devices contains functions that generate  * asynchronous callbacks. To simplify the application callback functions,  * these callbacks are executed on a thread owned by the SDK itself.  The  * SDK executes the application's callback function in a thread  * context so the application can allocate memory and preserve the information * it needs. The application can also use standard thread synchronization  * methods to ensure data integrity.  Due to the possibility of deadlock, the  * application cannot call back into the SDK during these callbacks  * unless explicitly noted.  There is no restriction in calling into the  * operating system or any other application interfaces. */