检查文件是否下载成功

Question

我要检查文件（例如.pdf文件）是否下载成功。

public class TestController : Controller
{
    public FilePathResult Index()
    {
        return File("path/to/file", "application/pdf");
    }
}

我能够找到此解决方案：

public class CheckedFileStreamResult : FileStreamResult
{
    public CheckedFileStreamResult(FileStream stream, string contentType)
    :base(stream, contentType)
    {
        DownloadCompleted = false;
    }

    public bool DownloadCompleted { get; set; }

    protected override void WriteFile(HttpResponseBase response)
    {
        var outputStream = response.OutputStream;
        using (FileStream)
        {
            var buffer = new byte[_bufferSize];
            var count = FileStream.Read(buffer, 0, _bufferSize);
            while(count != 0 && response.IsClientConnected)
            {                 
                outputStream.Write(buffer, 0, count);
                count = FileStream.Read(buffer, 0, _bufferSize);
            }
            DownloadCompleted = response.IsClientConnected;
        }
    }

    private const int _bufferSize = 0x1000;
}

我不知道如何在 OnResultExecuted 处理程序中检查 DownloadCompleted 标志。该操作方法返回 FilePathResult 。请指导我如何检查 OnResultExecuted 处理程序中的 DownloadCompleted 标志。我需要打字吗？