docs: function Log(opts) {
    if (this instanceof Log) {
      this.opts = opts;
      AsyncEvents.call(this);
      /*
       * Add a prototype method to Log class for each action.
       */
      var self = this;
      _.each(actionNames, function(name) {
        Log.prototype[name] = function() {
          var args = _.toArray(arguments);
          args.unshift(name);
          return self.__log.apply(self, args);
        };
      });
    } else {
      return new Log(opts);
    }
  }