The lecture helped me a lot in understanding RxJAVA. In each lecture, there is a beginning and end, an explanation of the next lecture, easy and core explanations and lecture materials, example codes, etc., so I thought that you prepared a lot while taking the lecture. In particular, the explanation of the operator used virtual data that could actually occur, so it was very helpful to imagine in which situations the operator would be good to use. I am still confused about why the producer and consumer have subscribe at the same time, so I will pay attention to that part when I watch the lecture again. Thank you for providing a great lecture.