Cookbook: echo
```bash
cargo run -p echo -- 127.0.0.1:8080
nc 127.0.0.1 8080Source: examples/echo. Binds with Runtime::add_tcp_listener, echoes in ProtocolHandler::receive. Press Enter to shut down.
```bash
cargo run -p echo -- 127.0.0.1:8080
nc 127.0.0.1 8080Source: examples/echo. Binds with Runtime::add_tcp_listener, echoes in ProtocolHandler::receive. Press Enter to shut down.