ng-select希望支持virtual-scroll

[lurenjiakang1]

当列表数据大的时候，页面渲染会卡顿

[ng-zorro-bot]

Hello @lurenjiakang1, your issue has been closed because it does not conform to our issue requirements. Please use the Issue Helper to create an issue, thank you!

你好 @lurenjiakang1，为了能够进行高效沟通，我们对 issue 有一定的格式要求，你的 issue 因为不符合要求而被自动关闭。你可以通过 issue 助手 来创建 issue 以方便我们定位错误。谢谢配合！

[ng-zorro-bot]

Translation of this issue:

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ng-select wants to support virtual-scroll

When the list data is large, the page rendering will be stuck.