Understanding multicasting

We have used the ConnectableObservable earlier in Chapter 2, Observables and Subscribers. Remember how cold Observables, such as Observable.range(), will regenerate emissions for each Observer? Let's take a look at the following code:

import io.reactivex.Observable;

public class Launcher {
    public static void main(String[] args) {

        Observable<Integer> threeIntegers  = Observable.range(1, 3);

        threeIntegers.subscribe(i -> System.out.println("Observer One: " + i));
        threeIntegers.subscribe(i -> System.out.println("Observer Two: " + i));
    }
}

The output is as follows:

Observer One: 1
Observer One: 2
Observer One: 3
Observer Two: 1
Observer Two: 2
Observer Two: 3

Here, Observer One received all three emissions and called onComplete(). After that, Observer Two received the three emissions (which...