我们将`SessionLocal()`请求的创建和处理放在一个`try`块中。

然后我们在finally块中关闭它。

通过这种方式，我们确保数据库会话在请求后始终关闭，即使在处理请求时出现异常也会关闭。

///

### 关于`request.state`

`request.state`是每个`Request`对象的属性。它用于存储附加到请求本身的任意对象，例如本例中的数据库会话。您可以在[Starlette 的关于`Request`state](https://www.starlette.io/requests/#other-state)的文档中了解更多信息。

对于这种情况下，它帮助我们确保在整个请求中使用单个数据库会话，然后关闭（在中间件中）。

### 使用`yield`依赖项与使用中间件的区别

在此处添加**中间件**与`yield`的依赖项的作用效果类似，但也有一些区别：

			z.FreeVersion, bts, err = msgp.ReadBoolBytes(bts)
			if err != nil {
				err = msgp.WrapError(err, "FreeVersion")
				return
			}
		case "Status":
			z.Status, bts, err = msgp.ReadStringBytes(bts)
			if err != nil {
				err = msgp.WrapError(err, "Status")
				return
			}
		default:
			bts, err = msgp.Skip(bts)
			if err != nil {
				err = msgp.WrapError(err)
				return
			}
		}

	// GlobalStaleUploadsExpiry - Expiry duration after which the uploads in multipart,
	// tmp directory are deemed stale.
	GlobalStaleUploadsExpiry = time.Hour * 24 // 24 hrs.

	// GlobalStaleUploadsCleanupInterval - Cleanup interval when the stale uploads cleanup is initiated.
	GlobalStaleUploadsCleanupInterval = time.Hour * 6 // 6 hrs.

	// Refresh interval to update in-memory iam config cache.

    client.send(message4)
    serverListener.assertTextMessage(message4)

    // Server to client message that shares context with message1.
    val message5 = message1 + message1
    server.send(message5)
    clientListener.assertTextMessage(message5)

    // Client to server message that shares context with message2.
    val message6 = message2 + message2
    client.send(message6)

 */

package com.google.common.util.concurrent;

import static com.google.common.base.Preconditions.checkNotNull;
import static java.util.concurrent.TimeUnit.MILLISECONDS;
import static junit.framework.Assert.assertEquals;
import static junit.framework.Assert.assertNotNull;
import static junit.framework.Assert.assertNull;
import static junit.framework.Assert.assertSame;

import com.google.common.testing.TearDown;

This [sample factory](https://github.com/square/okhttp/blob/master/samples/guide/src/main/java/okhttp3/recipes/PrintEvents.java) creates a unique ID for each call and uses that ID to differentiate calls in log messages.

```java
class PrintingEventListener extends EventListener {
  public static final Factory FACTORY = new Factory() {

### Bug or Regression

- Fix missing delete events on informer re-lists to ensure all delete events are correctly emitted and using the latest known object state, so that all event handlers and stores always reflect the actual apiserver state as best as possible ([#115899](https://github.com/kubernetes/kubernetes/pull/115899), [@odinuge](https://github.com/odinuge)) [SIG API Machinery]

 * the License.
 */

package com.google.common.util.concurrent;

import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.util.concurrent.Futures.getDone;
import static com.google.common.util.concurrent.MoreExecutors.rejectionPropagatingExecutor;
import static com.google.common.util.concurrent.Platform.restoreInterruptIfIsInterruptedException;

 * to use AtomicLongArray instead of sun.misc.Unsafe)
 */

package com.google.common.util.concurrent;

import static com.google.common.base.Preconditions.checkNotNull;
import static java.lang.Double.doubleToRawLongBits;
import static java.lang.Double.longBitsToDouble;

import com.google.common.annotations.GwtIncompatible;
import com.google.common.annotations.J2ktIncompatible;

		}()
	}
	wg.Wait()

	conn, ok := tx.ConnPool.(*gorm.PreparedStmtDB)
	AssertEqual(t, ok, true)
	AssertEqual(t, len(conn.Stmts), 2)
	for _, stmt := range conn.Stmts {
		if stmt == nil {
			t.Fatalf("stmt cannot bee nil")
		}
	}

	AssertEqual(t, sqlDB.Stats().InUse, 0)
}

func TestPreparedStmtInTransaction(t *testing.T) {
	user := User{Name: "jinzhu"}