Records an API newly generated by now-sdk transform (no prior Fluent representation).
now-sdk transform still runs plugins' toRecord() internally (to compute coalesce/explicit
keys and validate the round-trip for newly-generated Fluent code), which fires the same
setOnRecordCreated hook build does and populates entries — but none of that is a
developer authoring Fluent code, so transform must never emit fluent.authored from it.
Only fluent.transformed reflects what transform actually did.
Registers the pre-build keys registry so only new records emit fluent.authored events.
Starts a new build's collection window, returning the build_id in use (generating one if not supplied).
OptionalbuildId: string
Owns the full lifecycle of a single build's API usage telemetry: the
build_idthat correlates itsfluent.authoredevents with thebuildevent, the collected entries, and the per-API-name counts snapshot that survives afteremit()/clear()(so callers can still read "how many of each API did the last build produce" afterward).