重写Behavior，能够实现三种状态，原生只能实现两种,类似谷歌地图
Repository from Github https://github.comxiaogu-space/BottomSheetBehaviorRepository from Github https://github.comxiaogu-space/BottomSheetBehavior
重写Behavior，能够实现三种状态，原生只能实现两种