* **Intuitive**: Great editor support. <abbr title="also known as auto-complete, autocompletion, IntelliSense">Completion</abbr> everywhere. Less time debugging.
* **Easy**: Designed to be easy to use and learn. Less time reading docs.
* **Short**: Minimize code duplication. Multiple features from each parameter declaration. Fewer bugs.
* **Robust**: Get production-ready code. With automatic interactive documentation.

    // Call 1: set a deadline on the response body.
    val request1 = Request.Builder().url(server.url("/")).build()
    val response1 = client.newCall(request1).execute()
    val body1 = response1.body.source()
    assertThat(body1.readUtf8()).isEqualTo("abc")
    body1.timeout().deadline(5, TimeUnit.SECONDS)

    // Call 2: check for the absence of a deadline on the request body.

    // Append 10 more bytes to the source.
    source.append(newPreFilledByteArray(5, 10));

    // The stream reports no bytes... importantly, it doesn't read the byte at index 5 when it
    // should be reading the byte at index 10.
    // We could use a custom InputStream instead to make the read start at index 10, but since this
    // is a racy situation anyway, this behavior seems reasonable.
    assertEquals(-1, in.read());
  }

      stream.defaultWriteObject();
      stream.writeObject(inverse());
    }

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

  }

  private static final class JavaIoCreator extends TempFileCreator {
    @Override
    File createTempDir() {
      File baseDir = new File(JAVA_IO_TMPDIR.value());
      @SuppressWarnings("GoodTime") // reading system time without TimeSource
      String baseName = System.currentTimeMillis() + "-";

      for (int counter = 0; counter < TEMP_DIR_ATTEMPTS; counter++) {
        File tempDir = new File(baseDir, baseName + counter);

        }
    }

    @SuppressWarnings("unchecked")
    @Override
    public void readExternal(final ObjectInput s) throws IOException, ClassNotFoundException {
        final int size = s.readInt();
        header = new Entry(null, null, null);
        header.next = header;
        header.previous = header;
        for (int i = 0; i < size; i++) {
            addLast((E) s.readObject());
        }
    }

## 上下文管理器

### 什么是"上下文管理器"

"上下文管理器"是你可以在 `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">你可以使用`with`读取文件</a>：

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

 *       Future} is "completed" even if it is cancelled while its underlying work continues on a
 *       thread, an RPC, etc. The {@code Future} is also "completed" if it fails "early" -- for
 *       example, if the deadline expires on a {@code Future} returned from {@link
 *       Futures#withTimeout} while the {@code Future} it wraps continues its underlying work. So

	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())

	req, err := c.newRequest(ctx, httpMethod, u, body)
	if err != nil {
		return nil, &NetworkError{Err: err}
	}
	if length > 0 {
		req.ContentLength = length
	}

	_, expectTimeouts := ctx.Deadline()

	req, update := setupReqStatsUpdate(req)
	defer update()

	resp, err := c.httpClient.Do(req)
	if err != nil {
		if xnet.IsNetworkOrHostDown(err, expectTimeouts) {
			if !c.NoMetrics {