code: function(tweet, streamChannels){
      helpers.postprocessTweet(tweet, streamChannels);
      return helpers.emitPosprocessedTweet(tweet, streamChannels);
    }
docs: /*
  To execute when a tweet is received :
  - to posprocess the tweet
  - then emit the postprocessed tweet on the proper events
  @param {Object} tweet
  @param {StreamChannels} streamChannels
  @returns {StreamChannels}