Hello NiFi Devs, I logged this bug not too long ago: https://issues.apache.org/jira/browse/NIFI-10583
and I would like some validation on whether I took the right direction with the desired behaviour being that both ProcessSessions not mutate the flowfile passed in, rather than changing the MockProcessSession to mutate the flowfile passed in in addition to returning a new flowfile with the attributes added. Thanks, Eric
