For spring data reactive cassandra when repository methods are called is the entire result of the query loaded to memory before returning a flux

Question

I am new to reactive programming. Doing a POC on the cassandra/datastax with reactive spring data. I have executed some select query using the spring data ReactiveCassandraRepository. My doubt is about the internal working. When, for example, I trigger a findAll query it returns a Flux and I am able to see data using my REST client code. But my doubt is if I have 100 records as result of the query, will the spring data fetch those 100 records to memory and then stream it as Flux or is it actually when the client fetch for each row, the data is streaming all the way from database.