如何将Microsoft.Sharepoint.Client.ListItem转换为Microsoft.Sharepoint.Client.File？

using Microsoft.SharePoint.Client;

public void ConvertListItemToFile(ListItem listItem)
{
    // 获取文件的相关属性
    string filePath = listItem["FileRef"].ToString();
    string fileName = listItem["FileLeafRef"].ToString();
    long fileSize = (long)listItem["File_x0020_Size"];

    // 创建文件对象
    FileCreationInformation fileInfo = new FileCreationInformation();
    fileInfo.Url = filePath;
    fileInfo.Overwrite = true;
    fileInfo.Content = new byte[fileSize];

    // 将文件对象添加到文件夹中
    Folder folder = listItem.ParentList.RootFolder;
    File newFile = folder.Files.Add(fileInfo);

    listItem.Context.Load(newFile);
    listItem.Context.ExecuteQuery();
}