Bookkeeping information about what is downloaded must be maintained in the nonblocking download acknowledgement transaction.
This information should be updated in the publication_nonblocking_download_ack or nonblocking_download_ack scripts which is
called after the remote database successfully applies the download.
If a failure occurs or SendDownloadAck is OFF, these non-blocking download acknowledgement scripts are not called and the
download timestamp in the consolidated database is not updated. When testing your synchronization scripts you should artificially
cause failed downloads to ensure that your scripts can handle a failed download.