Buffering

The buffer() operator will gather emissions within a certain scope and emit each batch as a list or another collection type. The scope can be defined by a fixed buffer sizing or a timing window that cuts off at intervals or even slices by the emissions of another Observable.

Fixed-size buffering

The simplest overload for buffer() accepts a count argument that batches emissions in that fixed size. If we wanted to batch up emissions into lists of eight elements, we can do that as follows:

import io.reactivex.Observable;

public class Launcher {    
public static void main(String[] args) {
     Observable.range(1,50)
               .buffer(8)
               .subscribe(System.out::println);
   }
}

The output is as...