Starts a database activity stream to monitor activity on the database. For more information, see <a href="https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/DBActivityStreams.html"> Monitoring Amazon Aurora with Database Activity Streams</a> in the <i>Amazon Aurora User Guide</i> or <a href="https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/DBActivityStreams.html"> Monitoring Amazon RDS with Database Activity Streams</a> in the <i>Amazon RDS User Guide</i>.