Torrent programs download files in a random order. That causes streaming impossible. But there is a solution, you can enable sequential downloading and stream it. All you need is qBittorrent and VLC Player. Just dowload your .torrent file and open it with qBittorrent, select your download location and start downloading. Then right-click your torrent, select Download in sequential order. That’s all. Now you can open the video file with vlc player(or any player that supports incomplete file types) and watch it.
But there is a problem. Sequential downloading is not a very good thing. If you really want to watch the torrent while downloading, do that. But it causes low speed downloading and it’s against torrent’s logic. In normal time, never use it.
Here you can see how the progress is going. Normally, it should download the pieces of file randomly(not really random but we can call like that). But, as you can see, it downloads in order.