object WebSocketProtocol {
  /** Magic value which must be appended to the key in a response header. */
  internal const val ACCEPT_MAGIC = "258EAFA5-E914-47DA-95CA-C5AB0DC85B11"

  /*
  Each frame starts with two bytes of data.

   0 1 2 3 4 5 6 7    0 1 2 3 4 5 6 7
  +-+-+-+-+-------+  +-+-------------+
  |F|R|R|R| OP    |  |M| LENGTH      |
  |I|S|S|S| CODE  |  |A|             |
  |N|V|V|V|       |  |S|             |

			if e := enc.Encode(struct {
				Versions []version
			}{Versions: versions}); e != nil {
				return nil, e
			}
			data = b
		default:
			return nil, fmt.Errorf("unknown metadata version %d", minor)
		}

		if datajson {
			b, e := data.json()
			if e != nil {
				return nil, e
			}
			buf = bytes.NewBuffer(b)
		}

		return buf.Bytes(), nil
	}

    * Doğrulayıcılar en kompleks data şemalarının bile temiz ve kolay bir şekilde tanımlanmasına izin veriyor, ve hepsi JSON şeması olarak dokümante ediliyor
    * Pydantic, JSON objen ne kadar derin (nested) olursa olsun doğrulamasını ve gösterimini yapıyor
* **Genişletilebilir**:

These handlers are in charge of returning the default JSON responses when you `raise` an `HTTPException` and when the request has invalid data.

You can override these exception handlers with your own.

### Override request validation exceptions

When a request contains invalid data, **FastAPI** internally raises a `RequestValidationError`.

And it also includes a default exception handler for it.

try:
    import orjson
except ImportError:  # pragma: nocover
    orjson = None  # type: ignore


class UJSONResponse(JSONResponse):
    """
    JSON response using the high-performance ujson library to serialize data to JSON.

    Read more about it in the
    [FastAPI docs for Custom Response - HTML, Stream, File, others](https://fastapi.tiangolo.com/advanced/custom-response/).
    """

    def render(self, content: Any) -> bytes:

  override fun cancel() {
    canceled = true
    call?.cancel()
  }

  override fun onEvent(
    id: String?,
    type: String?,
    data: String,
  ) {
    listener.onEvent(this, id, type, data)
  }

  override fun onRetryChange(timeMs: Long) {
    // Ignored. We do not auto-retry.
  }

# Using the Request Directly

Up to now, you have been declaring the parts of the request that you need with their types.

Taking data from:

* The path as parameters.
* Headers.
* Cookies.
* etc.

And by doing so, **FastAPI** is validating that data, converting it and generating documentation for your API automatically.

But there are situations where you might need to access the `Request` object directly.

Prefer to use the `Annotated` version if possible.

///

```Python hl_lines="7-9  13"
{!> ../../docs_src/request_form_models/tutorial001.py!}
```

////

**FastAPI** will **extract** the data for **each field** from the **form data** in the request and give you the Pydantic model you defined.

## Check the Docs

You can verify it in the docs UI at `/docs`:

<div class="screenshot">

   * eagerly fetches data for each source when iterated (rather than producing sources that only
   * load data through their streams). Prefer using the {@link #concat(Iterable)} overload if
   * possible.
   *
   * @param sources the sources to concatenate
   * @return a {@code ByteSource} containing the concatenated data
   * @throws NullPointerException if any of {@code sources} is {@code null}

	return func(baseKey string, data []byte) []byte {
		if len(data) == 0 {
			return data
		}
		var buffer bytes.Buffer
		mac := hmac.New(sha256.New, key[:])
		mac.Write([]byte(baseKey))
		if _, err := sio.Encrypt(&buffer, bytes.NewReader(data), sio.Config{Key: mac.Sum(nil), CipherSuites: fips.DARECiphers()}); err != nil {