//filter 按照规则过滤
        Observable.just(0,1,2,3,4,5)
                .filter(new Func1<Integer, Boolean>() {
                    @Override
                    public Boolean call(Integer integer) {
                        return integer < 2;
                    }
                }).subscribe(new Action1<Integer>() {
            @Override
            public void call(Integer integer) {
                Log.i(TAG,"call:"+integer) ;
            }
        });