#logging

Your checkout logs a line at every step, which looks like good observability. Then a customer says their payment failed, and you find out what those logs can't tell you.

A tiny `createEvent(name, seed)` that accumulates fields over the life of a request via `.set()` and emits exactly one structured log line via `.emit()`, so a request that touches ten steps still produces one row instead of ten.

You're about to add logging to a new service, or you're staring at an existing one where every incident turns into a grep-and-guess session across a dozen disconnected log lines. Replace the step-by-step logs with one wide event per request.