- Configurar el header `Cache-Control: no-cache` para **evitar el almacenamiento en caché** del stream.

* Send a **"keep alive" `ping` comment** every 15 seconds when there hasn't been any message, to prevent some proxies from closing the connection, as suggested in the [HTML specification: Server-Sent Events](https://html.spec.whatwg.org/multipage/server-sent-events.html#authoring-notes).
* Set the `Cache-Control: no-cache` header to **prevent caching** of the stream.
* Set a special header `X-Accel-Buffering: no` to **prevent buffering** in some proxies like Nginx.

    When `yield`ed from a *path operation function* that uses
    `response_class=EventSourceResponse`, each `ServerSentEvent` is encoded
    into the [SSE wire format](https://html.spec.whatwg.org/multipage/server-sent-events.html#parsing-an-event-stream)
    (`text/event-stream`).

    If you yield a plain object (dict, Pydantic model, etc.) instead, it is
    automatically JSON-encoded and sent as the `data:` field.

- Définir l’en-tête `Cache-Control: no-cache` pour **empêcher la mise en cache** du flux.

## 技術細節 { #technical-details }

FastAPI 內建實作了一些 SSE 的最佳實務。

- 當 15 秒內沒有任何訊息時，傳送一次**「保活」`ping` 註解**，以避免某些代理伺服器關閉連線；此作法源自於[HTML 規範：Server-Sent Events](https://html.spec.whatwg.org/multipage/server-sent-events.html#authoring-notes)中的建議。
- 設定 `Cache-Control: no-cache` 標頭，以**防止快取**串流內容。
- 設定特殊標頭 `X-Accel-Buffering: no`，以**避免**在像 Nginx 這類代理中被**緩衝**。

- Надсилати **коментар «keep alive» `ping`** кожні 15 секунд, коли не було жодного повідомлення, щоб запобігти закриттю з'єднання деякими проксі, як рекомендовано у [Специфікації HTML: Події, надіслані сервером](https://html.spec.whatwg.org/multipage/server-sent-events.html#authoring-notes).
- Встановити заголовок `Cache-Control: no-cache`, щоб **запобігти кешуванню** потоку.

## 技术细节 { #technical-details }

FastAPI 开箱即用地实现了一些 SSE 的最佳实践。

- 当 15 秒内没有任何消息时，发送一个**保活 `ping` 注释**，以防某些代理关闭连接，正如 [HTML 规范：Server-Sent Events](https://html.spec.whatwg.org/multipage/server-sent-events.html#authoring-notes) 中建议的那样。
- 设置 `Cache-Control: no-cache` 响应头，**防止缓存**流。
- 设置特殊响应头 `X-Accel-Buffering: no`，以**防止**某些代理（如 Nginx）**缓冲**。

    ImmutableSet<String> validIsatapAddresses =
        ImmutableSet.of(
            "2001:db8::5efe:102:304",
            "2001:db8::100:5efe:102:304", // Private Multicast? Not likely.
            "2001:db8::200:5efe:102:304",
            "2001:db8::300:5efe:102:304" // Public Multicast? Also unlikely.
            );
    ImmutableSet<String> nonIsatapAddresses =
        ImmutableSet.of(
            "::1.2.3.4",
            "3ffe::1",

  /**
   * The HTTP <a href="http://html.spec.whatwg.org/multipage/semantics.html#hyperlink-auditing">
   * {@code Ping-From}</a> header field name.
   *
   * @since 19.0
   */
  public static final String PING_FROM = "Ping-From";

  /**
   * The HTTP <a href="http://html.spec.whatwg.org/multipage/semantics.html#hyperlink-auditing">
   * {@code Ping-To}</a> header field name.
   *

		auditLogDecom(ctx, "DecomCopyData", objInfo.Bucket, objInfo.Name, objInfo.VersionID, err)
	}()

	actualSize, err := objInfo.GetActualSize()
	if err != nil {
		return err
	}

	if objInfo.isMultipart() {
		res, err := z.NewMultipartUpload(ctx, bucket, objInfo.Name, ObjectOptions{
			VersionID:    objInfo.VersionID,
			UserDefined:  objInfo.UserDefined,
			NoAuditLog:   true,
			SrcPoolIdx:   idx,