SERVER-43859 exposed an issue where, for collections on standalones and non-replicated collections on replica sets, during collection creation, the object for the newly-created collection could be accessible prior to the storage transaction being committed. This was not a problem before SERVER-43859, since the MODE_X collection lock was held throughout the creation, preventing access to the collection object before the command completed. As of that ticket, we no longer take the exclusive lock, so the issue needs to be otherwise addressed.