k">While the session is open, this method returns a Map that the developer may
 use to store application specific information relating to this session
 instance. The developer may retrieve information from this Map at any time
 between the opening of the session and during the onClose() method. But outside
 that time, any information stored using this Map may no longer be kept by the
 container. Web socket applications running on distributed implementations of
 the web container should make any application 