是否支持控制自定义组件的可见性，比如仅包内可见

// library/index.ets  
export { MainPage } from './src/main/ets/components/MainPage/MainPage'
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// library/src/main/ets/components/MainPage/MainPage.ets 
@Component 
export struct MainPage { 
  @State message: string = 'Hello World' 
  build() { 
    Row() { 
      Column() { 
        Text(this.message) 
          .fontSize(50) 
          .fontWeight(FontWeight.Bold) 
      } 
      .width('100%') 
    } 
    .height('100%') 
  } 
}
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