//这俩暂未发现不同
_stateVar = State(initialValue: settingItem.wrappedValue)
_stateVar = State(wrappedValue: settingItem.wrappedValue)

@Binding var settingItem: SparkFormItem{
 willSet{
     settingItemState = newValue // settingItemState是@State变量
 }
}

@Binding var settingItem: SparkFormItem
init(settingItem: Binding<SparkFormItem>) {
 _settingItem = settingItem // 这里_settingItem的初始化不会改变self.settingItem的值
}