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。

当你使用 `yield` 创建一个依赖项时，**FastAPI** 会在内部将其转换为上下文管理器，并与其他相关工具结合使用。

var blobBody = []byte("<BLOB>")

// gzippedBody returns a dummy body placeholder for gzipped content
var gzippedBody = []byte("<GZIP>")

// Body - Return response body.
func (lrw *ResponseRecorder) Body() []byte {
	if lrw.Header().Get("Content-Encoding") == "gzip" {
		if lrw.body.Len() > 1<<20 {
			return gzippedBody
		}
		r, err := gzip.NewReader(&lrw.body)
		if err != nil {

		r.writeCond = sync.NewCond(&r.mu)
	}
	return r
}

// WithCancel sets a context to cancel the ring buffer.
// When the context is canceled, the ring buffer will be closed with the context error.
// A goroutine will be started and run until the provided context is canceled.
func (r *RingBuffer) WithCancel(ctx context.Context) *RingBuffer {
	go func() {
		<-ctx.Done()
		r.CloseWithError(ctx.Err())
	}()
	return r
}

	loadMappedPolicies(ctx context.Context, userType IAMUserType, isGroup bool, m *xsync.MapOf[string, MappedPolicy]) error
	saveIAMConfig(ctx context.Context, item any, path string, opts ...options) error
	loadIAMConfig(ctx context.Context, item any, path string) error
	deleteIAMConfig(ctx context.Context, path string) error
	savePolicyDoc(ctx context.Context, policyName string, p PolicyDoc) error

	}

	// Skip if no header was set.
	if !ok {
		return true
	}

	// If x-amz-content-sha256 is set and the value is not
	// 'UNSIGNED-PAYLOAD' we should validate the content sha256.
	switch v[0] {
	case unsignedPayload, unsignedPayloadTrailer:
		return true
	case emptySHA256:
		// some broken clients set empty-sha256
		// with > 0 content-length in the body,
		// we should skip such clients and allow

 -----

Maven Model

 This is strictly the model for Maven POM (Project Object Model) in <<<org.apache.maven.model>>> package,
 delegating content to {{{../../api/maven-api-model/index.html}Maven 4 API immutable model}}. All the effective model
 building logic from multiple POMs and building context is done in {{{../maven-model-builder/}Maven Model Builder}}.

 The following are generated from this model:

	}
}

func initConfigSubsystem(ctx context.Context, newObject ObjectLayer) error {
	// %w is used by all error returns here to make sure
	// we wrap the underlying error, make sure when you
	// are modifying this code that you do so, if and when
	// you want to add extra context to your error. This
	// ensures top level retry works accordingly.

	// Initialize config system.

 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package okhttp3.internal.platform

import android.content.Context
import android.os.Build
import android.os.StrictMode
import android.security.NetworkSecurityPolicy
import android.util.Log
import java.io.IOException
import java.lang.reflect.InvocationTargetException

	}
}

// getDiskInfos returns the disk information for the provided disks.
// If a disk is nil or an error is returned the result will be nil as well.
func getDiskInfos(ctx context.Context, disks ...StorageAPI) []*DiskInfo {
	res := make([]*DiskInfo, len(disks))
	opts := DiskInfoOptions{}
	for i, disk := range disks {
		if disk == nil {
			continue
		}

func (sys *NotificationSys) ServerInfo(ctx context.Context, metrics bool) []madmin.ServerProperties {
	reply := make([]madmin.ServerProperties, len(sys.peerClients))
	var wg sync.WaitGroup
	for i, client := range sys.peerClients {
		if client == nil {
			continue
		}
		wg.Add(1)
		go func(client *peerRESTClient, idx int) {
			defer wg.Done()
			ctx, cancel := context.WithTimeout(ctx, 10*time.Second)