For Biggie to be able to append its custom statistics to the output of the 'serverStatus' command, it will need to implement the ServerStatusSection interface.

Something similar was done for the WiredTiger storage engine, see:

https://github.com/mongodb/mongo/blob/master/src/mongo/db/storage/wiredtiger/wiredtiger_server_status.h

and

https://github.com/mongodb/mongo/blob/master/src/mongo/db/storage/wiredtiger/wiredtiger_server_status.cpp

It would suffice to add an empty server status section for Biggie.