// still alive. As ztunnel shouldn't send anything unless we send
			// something first, we expect to get an os.ErrDeadlineExceeded error
			// here if the connection is still alive.
			// note that unlike tcp connections, reading is a good enough test here.
			_, err := conn.readMessage(time.Second / 100)
			switch {
			case !errors.Is(err, os.ErrDeadlineExceeded):
				log.Debugf("ztunnel keepalive failed: %v", err)

### Что такое "контекстные менеджеры"

"Контекстные менеджеры" - это любые объекты Python, которые можно использовать в операторе `with`.

Например, <a href="https://docs.python.org/3/tutorial/inputoutput.html#reading-and-writing-files" class="external-link" target="_blank">можно использовать `with` для чтения файла</a>:

```Python
with open("./somefile.txt") as f:
    contents = f.read()
    print(contents)
```

	// Object operations.

	// GetObjectNInfo returns a GetObjectReader that satisfies the
	// ReadCloser interface. The Close method runs any cleanup
	// functions, so it must always be called after reading till EOF
	//
	// IMPORTANTLY, when implementations return err != nil, this
	// function MUST NOT return a non-nil ReadCloser.

		ContentType: mime.TypeByExtension(filepath.Ext(object)),
	}

	var rc io.ReadCloser

	if file.UncompressedSize64 > 0 {
		// There may be number of header bytes before the content.
		// Reading 64K extra. This should more than cover name and any "extra" details.
		end := file.Offset + int64(file.CompressedSize64) + 64<<10
		if end > zipObjInfo.Size {
			end = zipObjInfo.Size
		}

	if !opts.NoAuditLog {
		auditObjectErasureSet(ctx, object, &er)
	}

	if !opts.NoLock {
		// Lock the object before reading.
		lk := er.NewNSLock(bucket, object)
		lkctx, err := lk.GetRLock(ctx, globalOperationTimeout)
		if err != nil {
			return ObjectInfo{}, err
		}
		ctx = lkctx.Context()
		defer lk.RUnlock(lkctx)
	}

## 上下文管理器

### 什么是“上下文管理器”

“上下文管理器”是您可以在`with`语句中使用的任何Python对象。

例如，<a href="https://docs.python.org/zh-cn/3/tutorial/inputoutput.html#reading-and-writing-files" class="external-link" target="_blank">您可以使用`with`读取文件</a>：

```Python
with open("./somefile.txt") as f:
    contents = f.read()
    print(contents)
```

	if err != nil {
		return "", fmt.Errorf("request err: %v", err)
	}
	// {
	// 	bodyBuf, err := io.ReadAll(resp.Body)
	// 	if err != nil {
	// 		return "", fmt.Errorf("Error reading body: %v", err)
	// 	}
	// 	fmt.Printf("bodyBuf (for LDAP login page): %s\n", string(bodyBuf))
	// }

	// Fill the login form with our test creds:
	// fmt.Printf("login form url: %s\n", lastReq.URL.String())

func (er erasureObjects) newMultipartUpload(ctx context.Context, bucket string, object string, opts ObjectOptions) (*NewMultipartUploadResult, error) {
	if opts.CheckPrecondFn != nil {
		// Lock the object before reading.
		lk := er.NewNSLock(bucket, object)
		lkctx, err := lk.GetRLock(ctx, globalOperationTimeout)
		if err != nil {
			return nil, err
		}
		rctx := lkctx.Context()

      stream.writeObject(factory);
      stream.writeObject(backingMap());
    }

    @GwtIncompatible // java.io.ObjectInputStream
    @J2ktIncompatible
    @SuppressWarnings("unchecked") // reading data stored by writeObject
    private void readObject(ObjectInputStream stream) throws IOException, ClassNotFoundException {
      stream.defaultReadObject();

	}

	// httptest Recorder to capture all the response by the http handler.
	rec := httptest.NewRecorder()
	// reading the body to preserve it so that it can be used again for second attempt of sending unsigned HTTP request.
	// If the body is read in the handler the same request cannot be made use of.
	buf, err := io.ReadAll(anonReq.Body)