It seems like the logical way to work

It sucks for livestreams on youtube too, since it only starts downloading the next chunk of video when it's almost done playing through the current chunk and if you experience a hiccup, then youtube's solution is to send you back in the livestream (amount depends on latency setting of the streamer) so instead of getting a nice live stream, you could be going back as far as around 20 seconds in the past, so if you want to participate then you're going to be that slow on your reaction. Instead of waiting for the full 5 seconds of the buffer to play through before downloading the next chunk, I wish they'd query for the next chunk before then and not only that, but if there's a hiccup, don't send the stream back by so much, because also if you fall too far behind then it skips ahead. It's all over the place.