https://docs.mongodb.com/ruby-driver/master/tutorials/ruby-driver-change-streams/#resuming-a-change-stream just has next, there should also be a try_next example that allows the application to correctly advance resume token when there aren't documents being returned.

Related SO inquiry: https://stackoverflow.com/questions/63323190/get-resume-token-with-mongodb-java-driver-before-first-document-received-in-chan/63328009#63328009