attributeMapper

Maps a NormalizedLogEvent to the LogRecord attributes. Defaults to defaultAttributeMapper, which records the logger name plus the event's own key/value pairs.

Applied at emit time, on the caller that logged — synchronously inside the log()/append() call, before the event is queued for the drain coroutine (LogCapture.resolveAtEdge). A mapper may therefore fold ambient state (the session or game currently in progress, a request id, the current screen) into attributes and trust that a record carries the state the line was emitted under, not whatever it has become by the time the record is drained (#1630).

Two consequences:

• Keep it cheap and non-blocking. It runs on the application's logging thread, once per captured event, not once per drain batch. It is skipped for events that produce no record (below minLevel, or one of the exporter's own loggers), but it runs before the trace/sampling gate — so a mapper is paid for even when a wired TraceContextProvider later drops the event.

• It should not throw. A mapper that throws drops that one record; the failure is swallowed rather than propagated into the application's logging call.