Perform an unregister request against central server.
Function used to get unregistered from the system. This function is not needed to be called even while programming Af-Arch servers. It is automatically handled by Af-Arch layers.
|usr_function ||Function to be executed when the server response arrives. |
|usr_data ||User data passed to user_function.|
- TRUE if the query was executed, or FALSE if it wasn't