Two models run in a client-server, remote procedure call (RPC) communication pattern. The client model `maxMsgCli` sends requests and receives response to/from the server model `maxMsgSrv` via the deprecated `rpcCall` method (use `call` instead). The server model receives requests and send responses. This example demostrates the RPC pattern through the use of the `client_of` and `is_server` model parameters and the RPC interface classes/functions.
