What is the purpose of the ConcurrencyStamp column in the AspNetUsers table in the new ASP.NET MVC 6 identity?

As the name state, it’s used to prevent concurrency update conflict.

For example, there’s a UserA named Peter in the database
2 admins open the editor page of UserA, want to update this user.

1. Admin_1 opened the page, and saw user called Peter.
2. Admin_2 opened the page, and saw user called Peter (obviously).
3. Admin_1 updated user name to Tom, and save data. Now UserA in the db named Tom.
4. Admin_2 updated user name to Thomas, and try to save it.

What would happen if there’s no ConcurrencyStamp is Admin_1’s update will be overwritten by Admin_2’s update.
But since we have ConcurrencyStamp, when Admin_1/Admin_2 loads the page, the stamp is loaded. When updating data this stamp will be changed too.
So now step 5 would be system throw exception telling Admin_2 that this user has already been updated, since he ConcurrencyStamp is different from the one he loaded.