So in case of success or error either step we would have to do a logout . So to avoid code duplication both in end of try and catch block we can have a finally block (exit on done). Do a logout in this sequence. 

 Also it can hold good when we do a manual connection to a DB and irrespective of success or failure we want  to close connection.

 Main(Exit on success)

|

|----Try(Exit on Failure)

|

|----Catch(Exit on Done)

Finally(Exit on Done)