Stable id, unique within the app for this ad's lifetime.
Wall-clock epoch millis of the library's own observation of this ad, or
null when the library never saw it arrive.
Per provenance:
'pool/emulated-no-sdk-preloader': load completion observed by this
library. There is no hidden platform cache age underneath.'pool/sdk-managed-preloader': ad availability observed by this library
(correlated from the preload availability callback). Not the platform's
own cache age, and null when the library was not listening when the ad
became available (for example after a JS context reload).Neither value is the SDK's cache age. Wall clock matches the platform's own predicate basis; a monotonic companion may land with native wiring for lifecycle safety across clock changes.
Identity carried by every piece of inventory the library hands to a consumer, for correlation and diagnostics.
Shared by pooled ads and multi-format handles so the two read as siblings and so a log line from either can be correlated the same way.