Altering sensu events in redis

I saw this ticket, and am wondering if anything has changed since:

My use case:

I’d like to analyze some of the existing fields in an event, then add an additional field based on that analysis. I’d normally be fine with making the presentation layer smart enough to deal with this, but I have multiple consumers of the sensu-api and I don’t want to have to make all of them “smart”, and continue to update their logic when the analysis algorithm changes. It’d be much easier to do this at the sensu-server which is considered a central routing point for all of these events. My only need at the moment is to inspect an event and add a new field. I looked briefly at sensu extensions, but the documentation I found was old and the mutate feature only mutates data coming into a handler.