表示关于列出项目中包的异步请求。
The PackageManger Client class returns a ListRequest instance when you call the Client.List method to list the package dependencies of your project. Use this object to determine when the request is complete and to access the result, which is a PackageCollection instance.
| Error | 请求返回的错误（如果有）。 |
| IsCompleted | 请求是否已完成。 |
| Status | 请求状态。 |
| Result | 对请求的响应。 |