many vs. one call to observeOn

manyObserveOns.java

        Flowable.range(1, 10)
                .observeOn(Schedulers.io())
                .doOnNext(x -> System.out.println(Thread.currentThread().getName()))
                .observeOn(Schedulers.io())
                .doOnNext(x -> System.out.println(Thread.currentThread().getName()))
                .observeOn(Schedulers.io())
                .doOnNext(x -> System.out.println(Thread.currentThread().getName()))
                .observeOn(Schedulers.io())
                .doOnNext(x -> System.out.println(Thread.currentThread().getName()))
                .observeOn(Schedulers.io())
                .doOnNext(x -> System.out.println(Thread.currentThread().getName()))
                .observeOn(Schedulers.io())
                .doOnNext(x -> System.out.println(Thread.currentThread().getName()))
                .observeOn(Schedulers.io())
                .doOnNext(x -> System.out.println(Thread.currentThread().getName()))
                .observeOn(Schedulers.io())
                .doOnNext(x -> System.out.println(Thread.currentThread().getName()))
                .observeOn(Schedulers.io())
                .doOnNext(x -> System.out.println(Thread.currentThread().getName()))
                .blockingSubscribe(System.out::println);

manyObserveOnsOutput.txt

RxCachedThreadScheduler-8
RxCachedThreadScheduler-8
RxCachedThreadScheduler-8
RxCachedThreadScheduler-7
RxCachedThreadScheduler-8
RxCachedThreadScheduler-7
RxCachedThreadScheduler-6
RxCachedThreadScheduler-8
RxCachedThreadScheduler-6
RxCachedThreadScheduler-7
RxCachedThreadScheduler-5
RxCachedThreadScheduler-8
RxCachedThreadScheduler-5
RxCachedThreadScheduler-6
RxCachedThreadScheduler-7
RxCachedThreadScheduler-4
RxCachedThreadScheduler-6
RxCachedThreadScheduler-8
RxCachedThreadScheduler-3
RxCachedThreadScheduler-4
RxCachedThreadScheduler-7
RxCachedThreadScheduler-5
RxCachedThreadScheduler-3
RxCachedThreadScheduler-2
RxCachedThreadScheduler-8
RxCachedThreadScheduler-2
RxCachedThreadScheduler-4
RxCachedThreadScheduler-5
RxCachedThreadScheduler-6
RxCachedThreadScheduler-7
RxCachedThreadScheduler-4
RxCachedThreadScheduler-3
RxCachedThreadScheduler-1
RxCachedThreadScheduler-8
RxCachedThreadScheduler-1
RxCachedThreadScheduler-9
RxCachedThreadScheduler-8
RxCachedThreadScheduler-2
1
RxCachedThreadScheduler-3
RxCachedThreadScheduler-6
RxCachedThreadScheduler-7
RxCachedThreadScheduler-5
RxCachedThreadScheduler-7
RxCachedThreadScheduler-5
RxCachedThreadScheduler-2
RxCachedThreadScheduler-1
RxCachedThreadScheduler-9
RxCachedThreadScheduler-1
RxCachedThreadScheduler-4
RxCachedThreadScheduler-7
RxCachedThreadScheduler-4
RxCachedThreadScheduler-6
RxCachedThreadScheduler-3
RxCachedThreadScheduler-7
RxCachedThreadScheduler-2
2
RxCachedThreadScheduler-1
RxCachedThreadScheduler-9
RxCachedThreadScheduler-3
RxCachedThreadScheduler-5
RxCachedThreadScheduler-6
RxCachedThreadScheduler-4
RxCachedThreadScheduler-6
RxCachedThreadScheduler-2
3
RxCachedThreadScheduler-9
RxCachedThreadScheduler-1
4
RxCachedThreadScheduler-6
RxCachedThreadScheduler-3
RxCachedThreadScheduler-5
RxCachedThreadScheduler-9
RxCachedThreadScheduler-4
RxCachedThreadScheduler-5
RxCachedThreadScheduler-2
RxCachedThreadScheduler-3
RxCachedThreadScheduler-9
5
RxCachedThreadScheduler-2
RxCachedThreadScheduler-1
RxCachedThreadScheduler-4
RxCachedThreadScheduler-1
RxCachedThreadScheduler-5
RxCachedThreadScheduler-3
RxCachedThreadScheduler-9
RxCachedThreadScheduler-2
6
RxCachedThreadScheduler-9
RxCachedThreadScheduler-4
RxCachedThreadScheduler-1
7
RxCachedThreadScheduler-9
RxCachedThreadScheduler-3
8
9
RxCachedThreadScheduler-2
RxCachedThreadScheduler-1
RxCachedThreadScheduler-9
10

Process finished with exit code 0

oneObserveOn.java

        Flowable.range(1, 10)
                .observeOn(Schedulers.io())
                .doOnNext(x -> System.out.println(Thread.currentThread().getName()))
                .doOnNext(x -> System.out.println(Thread.currentThread().getName()))
                .doOnNext(x -> System.out.println(Thread.currentThread().getName()))
                .doOnNext(x -> System.out.println(Thread.currentThread().getName()))
                .doOnNext(x -> System.out.println(Thread.currentThread().getName()))
                .doOnNext(x -> System.out.println(Thread.currentThread().getName()))
                .doOnNext(x -> System.out.println(Thread.currentThread().getName()))
                .doOnNext(x -> System.out.println(Thread.currentThread().getName()))
                .doOnNext(x -> System.out.println(Thread.currentThread().getName()))
                .blockingSubscribe(System.out::println);
 

oneObserveOnOutput.txt

RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
2
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
3
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
4
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
5
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
6
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
7
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
8
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
9
RxCachedThreadScheduler-1
RxCachedThreadScheduler-1
10