The style guide states that the explicit inline
should not be used with inline methods.
classof is very common line method with a fair amount
on inconsistency:
$ git grep classof ./include | grep inline | wc -l
230
$ git grep classof ./include | grep -v inline | wc -l
257
I chose to target this method rather the larger change
this this method is often cargo-culted since its needed
in many classes. I considered doing the larger change
and removing all occurrences but that would be a much
larger change.