code: function() {
          for (var i=this.maps.length-1; i>=0; --i) {
              this.removeMap(this.maps[i]);
          }
          this.maps = null;
          this.tileQueue = null;
          this.tileQueueId = null;
          this.tileCache = null;
          this.tileCacheIndex = null;
          this._destroyed = true;
      }
docs: Method: destroy