Ainsi, elle enverra le premier élément, le client le recevra et commencera à le traiter, et vous pourriez être encore en train de produire l'élément suivant.

```mermaid
sequenceDiagram
    participant App
    participant Client

    App->>App: Produce Item 1
    App->>Client: Send Item 1
    App->>App: Produce Item 2
    Client->>Client: Process Item 1
    App->>Client: Send Item 2
    App->>App: Produce Item 3

То есть оно отправит первый элемент, клиент его получит и начнет обрабатывать, а вы в это время можете все еще генерировать следующий элемент.

```mermaid
sequenceDiagram
    participant App
    participant Client

    App->>App: Produce Item 1
    App->>Client: Send Item 1
    App->>App: Produce Item 2
    Client->>Client: Process Item 1
    App->>Client: Send Item 2
    App->>App: Produce Item 3

Тобто він надішле перший елемент, клієнт його отримає і почне обробляти, а ви в цей час уже можете створювати наступний елемент.

```mermaid
sequenceDiagram
    participant App
    participant Client

    App->>App: Produce Item 1
    App->>Client: Send Item 1
    App->>App: Produce Item 2
    Client->>Client: Process Item 1
    App->>Client: Send Item 2
    App->>App: Produce Item 3

新增于 FastAPI 0.134.0。

///

## 什么是流 { #what-is-a-stream }

“流式传输”数据意味着你的应用会在整段数据全部准备好之前，就开始把每个数据项发送给客户端。

也就是说，它会先发送第一个数据项，客户端会接收并开始处理它，而此时你的应用可能还在生成下一个数据项。

```mermaid
sequenceDiagram
    participant App
    participant Client

    App->>App: Produce Item 1
    App->>Client: Send Item 1
    App->>App: Produce Item 2
    Client->>Client: Process Item 1
    App->>Client: Send Item 2
    App->>App: Produce Item 3

    return f"Hello {salutation} {name}"
```

votre programme pourrait s'exécuter comme ceci :

```mermaid
sequenceDiagram

participant code as Code
participant function as say_hi()
participant execute as Execute function

    rect rgba(0, 255, 0, .1)
        code ->> function: say_hi(name="Camila")
        function ->> execute: execute function code

@lru_cache
def say_hi(name: str, salutation: str = "Ms."):
    return f"Hello {salutation} {name}"
```

tu programa podría ejecutarse así:

```mermaid
sequenceDiagram

participant code as Código
participant function as say_hi()
participant execute as Ejecutar función

    rect rgba(0, 255, 0, .1)
        code ->> function: say_hi(name="Camila")
        function ->> execute: ejecutar código de la función

Sie sendet also das erste Element, der Client empfängt es und beginnt mit der Verarbeitung, und Sie erzeugen währenddessen möglicherweise bereits das nächste Element.

```mermaid
sequenceDiagram
    participant App
    participant Client

    App->>App: Produce Item 1
    App->>Client: Send Item 1
    App->>App: Produce Item 2
    Client->>Client: Process Item 1
    App->>Client: Send Item 2
    App->>App: Produce Item 3

def say_hi(name: str, salutation: str = "Ms."):
    return f"Hello {salutation} {name}"
```

ваша программа может выполняться так:

```mermaid
sequenceDiagram

participant code as Code
participant function as say_hi()
participant execute as Execute function

    rect rgba(0, 255, 0, .1)
        code ->> function: say_hi(name="Camila")
        function ->> execute: execute function code

    assert such claim is referred to as "Participant") alleging that the
    Participant Software (meaning the Contributor Version where the
    Participant is a Contributor or the Original Software where the
    Participant is the Initial Developer) directly or indirectly
    infringes any patent, then any and all rights granted directly or
    indirectly to You by such Participant, the Initial Developer (if the

데이터를 "**스트리밍**"한다는 것은 애플리케이션이 전체 항목 시퀀스가 모두 준비될 때까지 기다리지 않고 클라이언트로 데이터 항목을 보내기 시작한다는 뜻입니다.

즉, 첫 번째 항목을 보내면 클라이언트는 그것을 받아 처리하기 시작하고, 그동안 애플리케이션은 다음 항목을 계속 생성할 수 있습니다.

```mermaid
sequenceDiagram
    participant App
    participant Client

    App->>App: Produce Item 1
    App->>Client: Send Item 1
    App->>App: Produce Item 2
    Client->>Client: Process Item 1
    App->>Client: Send Item 2
    App->>App: Produce Item 3