docs: function (elem)
      {
          if (elem === null) { return ; }
          if (typeof(elem.sort) === "function") {
              for (var i = 0; i < elem.length; i++) {
                  this._queueData(elem[i]);
              }
          } else if (typeof(elem.tree) === "function") {
              this._queueData(elem.tree());
          } else {
              this._queueData(elem);
          }
  
          this._proto._send();
      }