This is a common occurrence in China. The victim, probably an ebike rider, didn't bother to even look left or check behind before entering the intersection. I've seen far too many people do that, situational awareness is an after thought. The truck also appeared to be oblivious to the whole situation, just kept going even after the collision. Also, those trucks are often quite noisy, usually the brakes have a deafening howl, pretty hard even for the hearing impaired to ignore.
Legally, the truck is at fault, (same as the US) however the law is only applied if you get caught, usually after an incident. Traffic enforcement is a lost cause in China.
Taking the lane isn't always the best option if there is heavy traffic, sometimes the traffic lane can be more unpredictable than the bike lane. The traffic lane can suddenly stop, making it all too easy to get boxed in, surrounded by unskilled drivers with nowhere to go. Many times there will be motorists that will move over two or more lanes without signalling cutting off whoever happens to get in the way.
I always check for right hooks, then left hooks, and finally check for anyone that is pulling in from the right when going through intersections.
Mirror use is essential.
Here is another fine example of poor situational awareness: