docs: function EventSet(opt_events) {
      this.bounds_dirty_ = true;
      this.bounds_ = new tr.b.Range();
      this.length_ = 0;
      this.guid_ = tr.b.GUID.allocate();
      this.pushed_guids_ = {};
  
      if (opt_events) {
        if (opt_events instanceof Array) {
          for (var i = 0; i < opt_events.length; i++)
            this.push(opt_events[i]);
        } else if (opt_events instanceof EventSet) {
          this.addEventSet(opt_events);
        } else {
          this.push(opt_events);
        }
      }
    }