You can also read more about them in the [Wikipedia for Environment Variable](https://en.wikipedia.org/wiki/Environment_variable).

In many cases it's not very obvious how environment variables would be useful and applicable right away. But they keep showing up in many different scenarios when you are developing, so it's good to know about them.

	expected := false
	if locked != expected {
		t.Errorf("TestDualWriteLockTimedOut(): \nexpected %#v\ngot      %#v", expected, locked)
	}
}

// Test cases below are copied 1 to 1 from sync/rwmutex_test.go (adapted to use DRWMutex)

// Borrowed from rwmutex_test.go
func parallelReader(ctx context.Context, m *DRWMutex, clocked, cunlock, cdone chan bool) {

import java.math.BigInteger;
import org.jspecify.annotations.Nullable;

/**
 * A wrapper class for unsigned {@code int} values, supporting arithmetic operations.
 *
 * <p>In some cases, when speed is more important than code readability, it may be faster simply to
 * treat primitive {@code int} values as unsigned, using the methods from {@link UnsignedInts}.
 *
 * <p>See the Guava User Guide article on <a

Sending a body with a `GET` request has an undefined behavior in the specifications, nevertheless, it is supported by FastAPI, only for very complex/extreme use cases.

As it is discouraged, the interactive docs with Swagger UI won't show the documentation for the body when using `GET`, and proxies in the middle might not support it.

///

# 流式数据 { #stream-data }

如果你要流式传输可以结构化为 JSON 的数据，你应该[流式传输 JSON Lines](../tutorial/stream-json-lines.md)。

但如果你想流式传输纯二进制数据或字符串，可以按下面的方法操作。

/// info | 信息

自 FastAPI 0.134.0 起新增。

///

## 使用场景 { #use-cases }

如果你想流式传输纯字符串，例如直接来自某个 AI LLM 服务的输出，可以使用它。

你也可以用它来流式传输大型二进制文件，在读取的同时按块发送，无需一次性把所有内容读入内存。

你还可以用这种方式流式传输视频或音频，甚至可以在处理的同时生成并发送。

## 使用 `yield` 的 `StreamingResponse` { #a-streamingresponse-with-yield }

```

### Running Tests with Coverage

```bash
mvn clean jacoco:prepare-agent test jacoco:report
```

Coverage reports are generated in `target/site/jacoco/`.

## Common Use Cases

### E-commerce Search

```java
// Product search suggestions
SuggestItem product = new SuggestItem(
    new String[]{"iPhone 15 Pro", "Apple iPhone 15 Pro"},

import org.junit.Rule;
import org.junit.Test;
import org.junit.rules.TestName;
import org.opensearch.action.admin.indices.get.GetIndexResponse;

/**
 * Tests for Suggester index lifecycle operations including edge cases.
 * Covers: createIndexIfNothing, createNextIndex, switchIndex, removeDisableIndices
 */
public class SuggesterIndexLifecycleTest {
    static OpenSearchRunner runner;

    @Rule

///

/// note | 技術詳細

各 JSON オブジェクトは改行で区切られるため、内容にリテラルな改行文字は含められません。ですが、エスケープした改行（`\n`）は含められます。これは JSON 標準の一部です。

とはいえ、通常は気にする必要はありません。自動で処理されますので、読み進めてください。🤓

///

## ユースケース { #use-cases }

これは **AI LLM** サービス、**ログ**や**テレメトリ**、あるいは **JSON** アイテムとして構造化できる他の種類のデータをストリームするのに使えます。

/// tip | 豆知識

動画や音声などのバイナリデータをストリームしたい場合は、上級ガイドを参照してください: [データのストリーム](../advanced/stream-data.md)。

///

		}
		if ETag := reader.ETag(); !Equal(ETag, test.ETag) {
			t.Fatalf("Test %d: ETag mismatch: got %q - want %q", i, ETag, test.ETag)
		}
	}
}

var multipartTests = []struct { // Test cases have been generated using AWS S3
	ETags     []ETag
	Multipart ETag
}{
	{
		ETags:     []ETag{},
		Multipart: ETag{},
	},
	{
		ETags:     []ETag{must("b10a8db164e0754105b7a99be72e3fe5")},

import java.math.BigInteger;
import org.jspecify.annotations.Nullable;

/**
 * A wrapper class for unsigned {@code long} values, supporting arithmetic operations.
 *
 * <p>In some cases, when speed is more important than code readability, it may be faster simply to
 * treat primitive {@code long} values as unsigned, using the methods from {@link UnsignedLongs}.
 *
 * <p>See the Guava User Guide article on <a