函式在 `yield` 之前的部分，會在應用啟動前先執行。

`yield` 之後的部分，會在應用結束後再執行。

### 非同步內容管理器（Async Context Manager） { #async-context-manager }

你會看到這個函式被 `@asynccontextmanager` 裝飾。

它會把函式轉換成所謂的「**非同步內容管理器（async context manager）**」。

{* ../../docs_src/events/tutorial003_py310.py hl[1,13] *}

Python 中的**內容管理器（context manager）**可以用在 `with` 陳述式中，例如 `open()` 可以作為內容管理器使用：

```Python
with open("file.txt") as file:

		// Empty Content-Md5 header.
		{mustNewSignedEmptyMD5Request(http.MethodPut, "http://127.0.0.1:9000/", 5, bytes.NewReader([]byte("hello")), t), ErrInvalidDigest},
		// Short Content-Md5 header.
		{mustNewSignedShortMD5Request(http.MethodPut, "http://127.0.0.1:9000/", 5, bytes.NewReader([]byte("hello")), t), ErrInvalidDigest},
		// When request is properly signed, but has bad Content-MD5 header.

/**
 * A skeleton eventspy that does nothing other than helping implementors.
 * @since 3.0.2
 */
public abstract class AbstractEventSpy implements EventSpy {

    @Override
    public void init(Context context) throws Exception {}

    @Override
    public void onEvent(Object event) throws Exception {}

    @Override
    public void close() throws Exception {}

        DefaultProfileActivationContext context = new DefaultProfileActivationContext();

        context.setActiveProfileIds(request.getActiveProfileIds());
        context.setInactiveProfileIds(request.getInactiveProfileIds());
        context.setSystemProperties(request.getSystemProperties());
        // enrich user properties with project packaging

        this.profileActivationFilePathInterpolator = profileActivationFilePathInterpolator;
        return this;
    }

    @Override
    public boolean isActive(Profile profile, ProfileActivationContext context, ModelProblemCollector problems) {
        Activation activation = profile.getActivation();

        if (activation == null) {
            return false;
        }

        ActivationFile file = activation.getFile();

)

// loadClusterIAMMetrics - `MetricsLoaderFn` for cluster IAM metrics.
func loadClusterIAMMetrics(_ context.Context, m MetricValues, _ *metricsCache) error {
	m.Set(lastSyncDurationMillis, float64(atomic.LoadUint64(&globalIAMSys.LastRefreshDurationMilliseconds)))
	pluginAuthNMetrics := globalAuthNPlugin.Metrics()

		size += len(block)
	}
	return size
}

// Writes all the data blocks from encoded blocks until requested
// outSize length. Provides a way to skip bytes until the offset.
func writeDataBlocks(ctx context.Context, dst io.Writer, enBlocks [][]byte, dataBlocks int, offset int64, length int64) (int64, error) {
	// Offset and out size cannot be negative.
	if offset < 0 || length < 0 {
		return 0, errUnexpected
	}

			db.Statement.Settings.Delete("rows")
			db.Statement.Dest, db.Error = db.Statement.ConnPool.QueryContext(db.Statement.Context, db.Statement.SQL.String(), db.Statement.Vars...)
		} else {
			db.Statement.Dest = db.Statement.ConnPool.QueryRowContext(db.Statement.Context, db.Statement.SQL.String(), db.Statement.Vars...)
		}

		db.RowsAffected = -1
	}

    private final CIFSContext context;
    private final ScheduledExecutorService cleanupExecutor;
    private static final long DEFAULT_LEASE_CLEANUP_INTERVAL = 60000; // 60 seconds
    private static final int DEFAULT_LEASE_BREAK_TIMEOUT = 60; // 60 seconds per MS-SMB2

    /**
     * Create a new lease manager
     *
     * @param context CIFS context
     */
    public LeaseManager(CIFSContext context) {

// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package cmd

import (
	"context"
	"encoding/xml"
	"net/http"

	xhttp "github.com/minio/minio/internal/http"
	"github.com/minio/minio/internal/logger"
)

// writeSTSErrorResponse writes error headers
func writeSTSErrorResponse(ctx context.Context, w http.ResponseWriter, errCode STSErrorCode, err error) {
	stsErr := stsErrCodes.ToSTSErr(errCode)