RxJava2操作符take

发送者发送多个数据，通过take获取前N个数据，接收者接收前N个数据

 Observable sender = Observable.create(new ObservableOnSubscribe() {
        @Override
        public void subscribe(@NonNull ObservableEmitter e) throws Exception {

            e.onNext(1);
            e.onNext(2);
            e.onNext(3);
            e.onNext(4);
            e.onNext(5);

        }
    })
            .takeLast(2);                 //取前两个数据

    Consumer receiver = new Consumer() {
        @Override
        public void accept(@NonNull Integer integer) throws Exception {

            Log.i("zzz","integer: " + integer);

            // 1
            // 2
        }
    };

    sender.subscribe(receiver);