Often while one reviewer is reviewing a pull request, it can be merged by another reviewer because s/he does not know that there are more "future" comments coming.
Is it possible to add another state in the pull requests to indicate that these reviewers are looking at the pull req and the merger can check with them before hitting approve and merge.
I guess that is one way. I was looking for less restrictive option but I can see that if it is not that restrictive then what is the point.
I was only thinking this feature from a process visiblitly point of view, that when I look at a pull req I need to know if others have started reviewing it or not. I think I can just assume that all reviewers start reviewing asap.