Rx\Functional\Operator\DoOnNextTest::doOnNext_should_see_all_values PHP Method

    public function doOnNext_should_see_all_values()
    {
        $xs = $this->createHotObservable([onNext(150, 1), onNext(210, 2), onNext(220, 3), onNext(230, 4), onNext(240, 5), onCompleted(250)]);
        $i = 0;
        $sum = 2 + 3 + 4 + 5;
        $this->scheduler->startWithCreate(function () use($xs, &$i, &$sum) {
            return $xs->doOnNext(function ($x) use(&$i, &$sum) {
                $i++;
                return $sum -= $x;
            });
        });
        $this->assertEquals(4, $i);
        $this->assertEquals(0, $sum);
    }