Creating a Flowable

Earlier in this book, we used Observable.create() a handful of times to create our own Observable from scratch, which describes how to emit items when it is subscribed to, as shown in the following code snippet:

import io.reactivex.Observable;
import io.reactivex.schedulers.Schedulers;
public class Launcher {
    public static void main(String[] args) {
        Observable<Integer> source = Observable.create(emitter -> {
             for (int i=0; i<=1000; i++) {
                 if (emitter.isDisposed())
                     return;
                emitter.onNext(i);
             }
            emitter.onComplete();
         });
        source.observeOn(Schedulers.io())
                 .subscribe(System.out::println);
        sleep(1000);
     }
 }

The output is as follows:

 0
 1
 2
 3
 4
 ...

This Observable.create()will emit the integers 0 to 1000 and then call...