I updated the MR with the bound check, the serial mechanism taken from !8895, and making the locked map generic and aggregatable.
I kept most of the implementation more like it was, avoiding any `struct map` access from the view except for the serial checks because it'd be unsafe otherwise for the thread safe implementation, as it only wraps the IMap interface. It would require a more complicated design otherwise, as we would also need a thread safe/unsafe map view and iterator wrappers.