RDS snapshot export finished event category for event subscription

In the documentation on exporting DB snapshot data to Amazon S3, under "Monitoring snapshot exports", it says:

To track completion of the export workflow or to initiate another workflow, you can subscribe to Amazon Simple Notification Service topics.

However, when attempting to set up such a subscription, I cannot find an event category related to the end of an export task. Does such an event exist? If not, what alternatives exist to trigger a lambda function once an export task ended?