<img src="/img/tutorial/custom-response/image01.png">

## Available responses { #available-responses }

Here are some of the available responses.

Keep in mind that you can use `Response` to return anything else, or even create a custom sub-class.

/// note | Technical Details

You could also use `from starlette.responses import HTMLResponse`.

            if (messages != null) {
                messages.clear();
            }
        }
        this.lastAccessedAt = LocalDateTime.now();
    }

    /**
     * Trims the message history to keep only the most recent messages.
     *
     * @param maxMessages the maximum number of messages to retain
     */
    public void trimHistory(final int maxMessages) {
        synchronized (messagesLock) {

## Technische Details { #technical-details }

FastAPI implementiert einige bewährte SSE-Praktiken direkt out of the box.

- Alle 15 Sekunden, wenn keine Nachricht gesendet wurde, einen **„keep alive“-`ping`-Kommentar** senden, um zu verhindern, dass einige Proxys die Verbindung schließen, wie in der [HTML-Spezifikation: Server-Sent Events](https://html.spec.whatwg.org/multipage/server-sent-events.html#authoring-notes) vorgeschlagen.

{* ../../docs_src/server_sent_events/tutorial005_py310.py hl[14] *}

## Detalhes Técnicos { #technical-details }

O FastAPI implementa algumas boas práticas de SSE prontas para uso.

	return t.GetWithCtx(context.Background())
}

func (t *Cache[T]) update(ctx context.Context) error {
	val, err := t.updateFn(ctx)
	if err != nil {
		if t.opts.ReturnLastGood && t.val.Load() != nil {
			// Keep last good value, so update
			// does not return an error.
			return nil
		}
		return err
	}

	t.val.Store(&val)
	t.lastUpdateMs.Store(time.Now().UnixMilli())
	return nil

But when checking benchmarks and comparisons you should keep the following in mind.

## Benchmarks and speed { #benchmarks-and-speed }

When you check the benchmarks, it is common to see several tools of different types compared as equivalent.

            // xapth.<field>=<value>
        }

        // config.*
        public static class Config {
            public static final String KEEP_ORIGINAL_BODY = "keep.original.body";
            public static final String CLEANUP_ALL = "cleanup.all";
            public static final String CLEANUP_URL_FILTERS = "cleanup.urlFilters";
            public static final String JCIFS_PREFIX = "jcifs.";

There is some assistance in the IDE for this plus a lot of validation that is applied at build time and on CI, but it is useful to keep these constraints in mind as well.

See [Gradle runtimes](runtimes.md) for a list of these runtimes and more details.

### Build execution model

* data validation
* data serialization
* data documentation, etc.

This works the same way as with Pydantic models. And it is actually achieved in the same way underneath, using Pydantic.

/// info

Keep in mind that dataclasses can't do everything Pydantic models can do.

So, you might still need to use Pydantic models.

type Sub[T Maskable] struct {
	ch     chan T
	types  Mask
	filter func(entry T) bool
}

// PubSub holds publishers and subscribers
type PubSub[T Maskable, M Maskable] struct {
	// atomics, keep at top:
	types          uint64
	numSubscribers int32
	maxSubscribers int32

	// not atomics:
	subs []*Sub[T]
	sync.RWMutex
}

// Publish message to the subscribers.