code: private Toolbox _addFeature(Feature value) {
          if (value == null) {
              return this;
          }
          //第一个字母转小写
          String name = value.getClass().getSimpleName();
          name = name.substring(0, 1).toLowerCase() + name.substring(1);
          _addFeatureOnce(name, value);
          return this;
      }
docs: 添加组件
  
  @param value
  @return