### 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)
```

在底层，`open("./somefile.txt")`创建了一个被称为"上下文管理器"的对象。

当 `with` 代码块结束时，它会确保关闭文件，即使发生了异常也是如此。

That's why in this example we have to declare it in the `response_model` parameter.

...but continue reading below to see how to overcome that.

## Return Type and Data Filtering { #return-type-and-data-filtering }

    HTTP 408 Request Timeout. If retries are enabled, OkHttp will retry exactly
    once in response to a 408.
 *  Fix: Don't crash when reading the empty `HEAD` response body if it specifies
    a `Content-Length`.
 *  Fix: Don't crash if the thread is interrupted while reading the public
    suffix database.
 *  Fix: Use relative resource path when loading the public suffix database.

        assertEquals(TransPeekNamedPipeResponse.STATUS_LISTENING, response.getStatus());
        // Middle bytes were read but not used
    }

    @Test
    @DisplayName("Test consecutive reads update state correctly")
    void testConsecutiveReads() {
        // First read
        byte[] buffer1 = new byte[10];
        SMBUtil.writeInt2(100, buffer1, 0);
        SMBUtil.writeInt2(0, buffer1, 2);

import org.eclipse.aether.resolution.VersionResult;
import org.eclipse.aether.transfer.ArtifactNotFoundException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Default artifact descriptor reader.
 *
 * @deprecated since 4.0.0, use {@code maven-api-impl} jar instead
 */
@Named
@Singleton
@Deprecated(since = "4.0.0")
public class DefaultArtifactDescriptorReader implements ArtifactDescriptorReader {

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

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

	derrs := make([]error, len(poolIndices))
	dobjects := make([]ObjectInfo, len(poolIndices))

	// Delete concurrently in all server pools that reported no error or read quorum error
	// where the read quorum issue is from metadata inconsistency.
	var wg sync.WaitGroup
	for idx, pe := range poolIndices {
		if v, ok := pe.Err.(InsufficientReadQuorum); ok && v.Type != RQInconsistentMeta {

* **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.

   ({{{./xref/org/apache/maven/model/validation/DefaultModelValidator.html}source}})

   []

 * phase 2, with optional plugin processing

   ** Build up a raw model by re-reading the file and enriching it based on information available in the reactor. Some features:

      *** Resolve version of versionless parents based on relativePath (including ci-friendly versions)

        // Test user boost
        item.setUserBoost(2.0f);
        assertEquals(2.0f, item.getUserBoost(), 0.001f);

        // Test readings
        String[][] newReadings = { { "read1", "read2" }, { "read3" } };
        item.setReadings(newReadings);
        assertArrayEquals(newReadings, item.getReadings());

        // Test fields
        String[] fields = { "field1", "field2" };