OnWorkEnd is a TWorkEndEvent property that represents the event handler signalled when completing a read or write operation on the connection. OnWorkEnd is generally used to finalize progress indicators or GUI components when an IO operation is completed. 

OnWorkEnd is assigned to the TWorkEndEvent event handler in IOHandler when the value for the IOHandler property is assigned. 

TIdTCPConnection contains an internal method normally assigned to OnWorkEnd. Applications can assign a procedure to the event handler to allow responsing the TWorkEndEvent notification. 

TWorkEndEvent 

TIdIOHandler.OnWorkEnd 

IOHandler