Three models run in a client-server, remote procedure call (RPC) communication pattern. The two client models (`client1` & `client2`) send requests and receive response to/from the server model `server` via the deprecated `call` method. 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. The `client1` & `client2` models also send request/response pairs to files in the temporary directory and receive parameters via the command line as specified in the YAML (both model call the same source code). The `server` model receives parameters as input from a file.
