docs: function () {
              var fc = this.freeCount, def, defQueue = this.__deferredQueue;
              while (fc-- >= 0 && defQueue.count) {
                  def = defQueue.dequeue();
                  var conn = this.getObject();
                  if (conn) {
                      def.callback(conn);
                  } else {
                      throw new Error("UNEXPECTED ERROR");
                  }
                  fc--;
              }
          }