我有一个async函数，它创建一个读流并将其写入http响应，如下所示：

let handle = await getFile();
    let stream = handle.createReadStream();
    let stat = await handle.stat();
    res.setHeader("content-length", stat.size);
    res.setHeader("content-type", "application/octet");
    res.statusCode = 200;
    stream.pipe(res);
    stream.on('close', () => {
      handle.close();
      res.end();
    });

正如您所看到的，当流关闭时，我关闭了句柄，同时也结束了响应。然而，我偶尔会看到node记录如下内容：

(node:54119) Warning: Closing file descriptor 21 on garbage collection
(Use `node --trace-warnings ...` to show where the warning was created)
(node:54119) [DEP0137] DeprecationWarning: Closing a FileHandle object on garbage collection is deprecated. Please close FileHandle objects explicitly using FileHandle.prototype.close(). In the future, an error will be thrown if a file descriptor is closed during garbage collection.

我的HTTP响应中没有错误，并且我已经通过日志验证了我的handle.close()正在为每个请求调用。为什么node认为我有未关闭的文件描述符？