## API
### TDRefreshHeader
#### 简介
TDesign刷新头部
 结合EasyRefresh类实现下拉刷新,继承自Header类，字段含义与父类一致
#### 默认构造方法

| 参数 | 类型 | 默认值 | 说明 |
| --- | --- | --- | --- |
| key | Key? | - | Key |
| extent |  | 48.0 |  |
| triggerDistance |  | 48.0 |  |
| float |  | false |  |
| completeDuration |  | - |  |
| enableHapticFeedback |  | true |  |
| enableInfiniteRefresh |  | false |  |
| overScroll |  | true |  |
| loadingIcon | TDLoadingIcon | TDLoadingIcon.circle | loading样式 |
| backgroundColor | Color? | - | 背景颜色 |