yield ServerSentEvent(data="hello", event="greeting", id="1")
    yield ServerSentEvent(data={"key": "value"}, event="json-data", id="2")
    yield ServerSentEvent(comment="just a comment")
    yield ServerSentEvent(data="retry-test", retry=5000)


@app.get("/items/stream-mixed", response_class=EventSourceResponse)
async def sse_items_mixed() -> AsyncIterable[Item]:
    yield items[0]
    yield ServerSentEvent(data="custom-event", event="special")

    if data_str is not None:
        for line in data_str.splitlines():
            lines.append(f"data: {line}")

    if id is not None:
        lines.append(f"id: {id}")

    if retry is not None:
        lines.append(f"retry: {retry}")

    lines.append("")
    lines.append("")
    return "\n".join(lines).encode("utf-8")


# Keep-alive comment, per the SSE spec recommendation

        response.setStatus(429);
        response.setContentType("application/json;charset=UTF-8");
        response.setHeader("Retry-After", String.valueOf(RETRY_AFTER_SECONDS));
        response.getWriter()
                .write("{\"response\":{\"status\":9,\"message\":\"Server is busy. Please retry after " + RETRY_AFTER_SECONDS
                        + " seconds.\",\"retry_after\":" + RETRY_AFTER_SECONDS + "}}");
    }

/// info | 정보

FastAPI 0.135.0에 추가되었습니다.

///

## Server-Sent Events란 { #what-are-server-sent-events }

SSE는 서버에서 클라이언트로 HTTP를 통해 데이터를 스트리밍하기 위한 표준입니다.

각 이벤트는 `data`, `event`, `id`, `retry`와 같은 "필드"를 가진 작은 텍스트 블록이며, 빈 줄로 구분됩니다.

다음과 같습니다:

```
data: {"name": "Portal Gun", "price": 999.99}

data: {"name": "Plumbus", "price": 32.99}

```

async def stream_items() -> AsyncIterable[ServerSentEvent]:
    yield ServerSentEvent(comment="stream of item updates")
    for i, item in enumerate(items):

     */
    fun withSocketFactory(socketFactory: SocketFactory): Chain

    /**
     * Returns true if the call should retry on connection failures.
     */
    val retryOnConnectionFailure: Boolean

    /**
     * Returns a new chain with the specified retry on connection failure setting.
     */
    fun withRetryOnConnectionFailure(retryOnConnectionFailure: Boolean): Chain

    /**

## What are Server-Sent Events? { #what-are-server-sent-events }

SSE is a standard for streaming data from the server to the client over HTTP.

Each event is a small text block with "fields" like `data`, `event`, `id`, and `retry`, separated by blank lines.

It looks like this:

```
data: {"name": "Portal Gun", "price": 999.99}

data: {"name": "Plumbus", "price": 32.99}

```

    }

    // ===================================================================================
    //                                                             Retry Limit
    //                                                             ============

    @Test
    public void test_tryStartOperation_singleArg_delegatesToTwoArg() {

    ```kotlin
    if (credential == response.request.header("Authorization")) {
      return null // If we already failed with these credentials, don't retry.
     }
    ```

    You may also skip the retry when you’ve hit an application-defined attempt limit:

    ```kotlin

async def stream_items() -> AsyncIterable[Item]:
    yield Item(name="Plumbus", price=32.99)
    yield Item(name="Portal Gun", price=999.99)
```

For full control over SSE fields (`event`, `id`, `retry`, `comment`), yield `ServerSentEvent` instances:

```python
from collections.abc import AsyncIterable

from fastapi import FastAPI
from fastapi.sse import EventSourceResponse, ServerSentEvent

app = FastAPI()