Github user justinleet commented on the issue:
https://github.com/apache/metron/pull/1213
Re: callback vs list. I'm pretty neutral on which one we do. I probably
have a slight preference towards the callbacks, just because it more closely
matches the original behavior, but I don't think it makes a huge difference in
the implementation (and let me know if it does).
@merrimanr Can you look into Travis?---
