Balancing KEYTIMEOUT delay and key binding integrity in zsh line editor

The zsh line editor uses the KEYTIMEOUT parameter, measured in hundredths of a second, to determine how long it waits after an escape‑sequence prefix before treating the following keystrokes as part of a complete key sequence.

When the timer expires, zsh processes the bytes received so far, which can introduce a perceptible pause after pressing Escape or a modifier key; this behavior is documented in zshparam and is independent of concurrent request handling.

What KEYTIMEOUT value minimizes the pause while preventing premature splitting of multi‑key bindings? How can the impact be reliably measured without altering system defaults?