deadlock.java

        ConnectableObservable<Boolean> booleanObservable = Observable
                .fromCallable(() -> {
                    Thread.sleep(1_000);
                    return true;
                }).startWith(false)
                .subscribeOn(Schedulers.io())
                .replay(2);

        Disposable sub1 = booleanObservable
                .doOnSubscribe(disposable -> {
                    printCurrentThread("SUBSCRIBED1");
                })
                .observeOn(AndroidSchedulers.mainThread())
                .subscribe(aBoolean -> {
                    printCurrentThread("1SubCallback: " + String.format("%1$s", aBoolean));
                });

        booleanObservable.connect();

        try {
            Thread.sleep(2_000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }

        booleanObservable.doOnSubscribe(disposable -> {
            printCurrentThread("SUBSCRIBED2");
        }).observeOn(AndroidSchedulers.mainThread())
                .subscribe(aBoolean -> {
                    if (!aBoolean) {
                        // show loading here:::::
                        printCurrentThread("2SubCallback_showLoading: " + String.format("%1$s", aBoolean));
                    } else {
                        printCurrentThread("2SubCallback_doStuff: " + String.format("%1$s", aBoolean));
                    }
                });