Local echo always felt like a handy feature for any kind of laggy terminal app, not just ssh / mosh.

I imagine such a tool would emulate a terminal a la screen / tmux, and just print what you type until the underlying program outputs to stdout, at which point it undoes what you typed and replays the stdout? I realise I may be betraying a complete lack of understanding of how Unix terminals actually work :)

Is there a Unix utility that implements a local-echo wrapper?