swift xib免协议加载view

如果是控制器，可以直接创建
如果是view

extension UINib{
    static func loadFrom<T:UIView>(_ type:T.Type ,owner: String? = nil , options: [UINib.OptionsKey : Any]? = nil) -> T {
        let nibName = String.init(describing: type)
        let nib = UINib.init(nibName: nibName, bundle: nil)
        let instantiation:T = nib.instantiate(withOwner: owner, options: options).first as! T
        return instantiation
    }
}

UINib.loadFrom(XXX)

此内容参照其他作者协议版本进行了优化
省去了添加协议才能创建的问题