Important
Before the following points make sure, that 127.0.0.1:9999 and 127.0.0.1:3030 is not in use.
cargo run -- -s
cargo run -- -p
cargo run -- -c
{ "jsonrpc": "2.0", "method": "say_hello", "params": "null", "id":1 }
{ "jsonrpc": "2.0", "method": "add", "params": [1, 2], "id":2 }
{ "jsonrpc": "2.0", "method": "exit", "params": null, "id": 3 }