es"><i>implementation</i>.&nbsp; This is an important feature and should be considered carefully.&nbsp; After the client call completes, the server may wish to call the client back (send a message to an object on the client).&nbsp; In general, this won't work, unless the client is in the middle of sending another message to the server.&nbsp; This is because there has to be a thread of execution waiting to serve incoming requests.&nbsp; The thread executing the client request pauses for the reply and will, c