use nebkor_maelstrom::{Body, Message, Node, Runner}; struct Echo; impl Node for Echo { fn handle(&mut self, runner: &Runner, msg: Message) { let typ = &msg.body.typ; if typ.as_str() == "echo" { let body = Body::from_type("echo_ok").with_payload(msg.body.payload.clone()); runner.reply(&msg, body); } } } fn main() { let node = Echo; let runner = Runner::new(node); runner.run(None); }