code: function() {
      var self = this;
      if (self._deactivated)
        return;
      self._deactivated = true;
      self._callStopCallbacks();
      Package.facts && Package.facts.Facts.incrementServerFact(
        "livedata", "subscriptions", -1);
    }
docs: This calls all stop callbacks and prevents the handler from updating any SessionCollectionViews further. It's used when the user unsubscribes or disconnects, as well as during setUserId re-runs. It does *NOT* send removed messages for the published objects; if that is necessary, call _removeAllDocuments first.