You might want to read up on the design of mosh. The way to tackle this is not to "buffer output up". In fact, the way to tackle this is the opposite of filli

You might want to read up on the design of mosh. The way to tackle this is not to "buffer output up". In fact, the way to tackle this is the opposite of filling up buffers with output. It is to decouple the terminal emulation from the rendering. Mosh runs the terminal emulator on the remote server machine, and transmits snapshots of state (using a difference algorithm for efficiency) at regular intervals over the network to the client, which renders the terminal state snapshots to the display on the local client.