Add a connection state listener to this DOFConnection. 
It will be called immediately with the current state of the connection.
A listener must be unique among this connection's set of state listeners to be added successfully.
- Parameters
 - 
  
    | self | The DOFConnection. This must not be NULL.  | 
    | listener | The listener to be called whenever the connection state changes. This must not be NULL. | 
  
   
- Return values
 - 
  
    | TRUE | if listener was successfully added to the connection.  | 
  
   
- Exceptions
 - 
  
    | FALSE | if the listener could not be added to the connection, either because of an illegal argument or because the listener is already added to the connection. | 
  
   
- See Also
 - DOFConnection_RemoveStateListener