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:

        DefaultProfileActivationContext context = new DefaultProfileActivationContext();

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

	// OsOpen allows overriding default function.
	OsOpen = os.Open
	// OsOpenFile allows overriding default function.
	OsOpenFile = os.OpenFile
)

// ReadFileWithFileInfo reads the named file and returns the contents.
// A successful call returns err == nil, not err == EOF.
// Because ReadFile reads the whole file, it does not treat an EOF from Read
// as an error to be reported.

)

// loadClusterReplicationMetrics - `MetricsLoaderFn` for cluster replication metrics
// such as transfer rate and objects queued.
func loadClusterReplicationMetrics(ctx context.Context, m MetricValues, c *metricsCache) error {
	st := globalReplicationStats.Load()
	if st == nil {
		return nil
	}

	qs := st.getNodeQueueStatsSummary()

	qt := qs.QStats

    @Mock
    private Configuration config;

    @Mock
    private CIFSContext context;

    @Mock
    private SmbTransportImpl transport;

    @BeforeEach
    void setUp() throws Exception {
        MockitoAnnotations.openMocks(this);
        when(session.getConfig()).thenReturn(config);
        when(session.getContext()).thenReturn(context);
        when(session.getTransport()).thenReturn(transport);

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

package grid

import (
	"context"
	"fmt"
	"net/http"
	"strings"
	"time"

	"github.com/minio/madmin-go/v3"
	"github.com/minio/minio/internal/pubsub"
)

// TraceParamsKey allows to pass trace parameters to the request via context.
// This is only needed when un-typed requests are used.

                        mergeDependency(dependency, managedDependency, false, context);
                    }
                }
            }
        }

        @Override
        protected void mergeDependency_Optional(
                Dependency target, Dependency source, boolean sourceDominant, Map<Object, Object> context) {
            // optional flag is not managed
        }

        @Override

    tempDir = Files.createTempDirectory("MoreFilesTest");
  }

  @Override
  protected void tearDown() throws Exception {
    if (tempDir != null) {
      // delete tempDir and its contents
      Files.walkFileTree(
          tempDir,
          new SimpleFileVisitor<Path>() {
            @Override
            public FileVisitResult visitFile(Path file, BasicFileAttributes attrs)

}

void TFE_ContextExportRunMetadata(TFE_Context* ctx, TF_Buffer* buf,
                                  TF_Status* status) {
  auto* context = tensorflow::unwrap(ctx);
  status->status = context->AsyncWait();
  if (!status->status.ok()) return;
  auto run_metadata = context->ExportRunMetadata();
  status->status = MessageToBuffer(*run_metadata, buf);
}

namespace {

        final Hashtable<String, String> env = new Hashtable<>();
        putEnv(env, Context.INITIAL_CONTEXT_FACTORY, initialContextFactory);
        putEnv(env, Context.SECURITY_AUTHENTICATION, securityAuthentication);
        putEnv(env, Context.PROVIDER_URL, providerUrl);
        putEnv(env, Context.SECURITY_PRINCIPAL, principal);
        putEnv(env, Context.SECURITY_CREDENTIALS, credntials);