Buffering

The buffer() operator gathers emissions within a certain scope and emits 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 as the buffer size and groups emissions in the batches of the specified size. If we wanted to batch up emissions into lists of eight elements, we can do that as follows:

import io.reactivex.rxjava3.core.Observable;

public class Ch7_01 {
    public static void main(String[] args) {
        Observable.range(1, 50)
                  .buffer(8)
                  .subscribe(System...