TUniquePtr< FConcertSessionSerializedPayload > EventPayload
The activity event payload usable for activity inspection. Might be null if it was not requested or did not provide insightful information.
If the activity type is 'transaction' and EventPayload is not null, it contains a FConcertSyncTransactionEvent with full transaction data.
If the activity type is 'package' and EventPayload is not null, it contains a FConcertSyncPackageEvent with the package meta data only.
Not set for other activity types (connection/lock).