Return a Halt object when you want to terminate the execution of all subsequent subscribers as well as the wrapped method if it has not exectued yet. Useful for Do.before subscribers.
Do.Haltmsg
                    
                retVal
                    
                
                
                Defined in
                
            
        
        
        event-custom/js/event-do.js:336
        
        
msg
                        String
                    
                    
                    (optional) Explanation of why the termination was done
retVal
                        Any
                    
                    
                    Return value passed to code that invoked the wrapped function.