*
   * @since 20.0
   */
  public static final String FORWARDED = "Forwarded";

  /**
   * The HTTP {@code Follow-Only-When-Prerender-Shown} header field name.
   *
   * @since 17.0
   */
  public static final String FOLLOW_ONLY_WHEN_PRERENDER_SHOWN = "Follow-Only-When-Prerender-Shown";

  /** The HTTP {@code Host} header field name. */
  public static final String HOST = "Host";

  /**

 *
 *  * Application Layer Protocol Negotiation (ALPN) enables the HTTPS port (443) to be used to
 *    negotiate HTTP/2.
 *
 * Unfortunately, older HTTPS servers refuse to connect when such options are presented. Rather than
 * avoiding these options entirely, this class allows a connection to be attempted with modern
 * options and then retried without them should the attempt fail.
 *
 * ## Connection Reuse
 *

Y muchos equipos utilizan solo `PUT`, incluso para actualizaciones parciales.

Eres **libre** de usarlos como desees, **FastAPI** no impone ninguna restricción.

Pero esta guía te muestra, más o menos, cómo se pretende que se usen.

///

### Uso del parámetro `exclude_unset` de Pydantic

Si quieres recibir actualizaciones parciales, es muy útil usar el parámetro `exclude_unset` en el `.model_dump()` del modelo de Pydantic.

    when a request body needs to cancel its own call.


## Version 4.2.1

_2019-10-02_

 *  Fix: In 4.1.0 we introduced a performance regression that prevented connections from being
    pooled in certain situations. We have good test coverage for connection pooling but we missed
    this because it only occurs if you have proxy configured and you share a connection pool among

### サブモデルを型として使用

そして、それを属性の型として使用することができます:

{* ../../docs_src/body_nested_models/tutorial004.py hl[20] *}

これは **FastAPI** が以下のようなボディを期待することを意味します:

```JSON
{
    "name": "Foo",
    "description": "The pretender",
    "price": 42.0,
    "tax": 3.2,
    "tags": ["rock", "metal", "bar"],
    "image": {
        "url": "http://example.com/baz.jpg",
        "name": "The Foo live"
    }
}
```

 * newHasher().putByte(b1).putBytes(new byte[] { b2, b3 }).hash()
 * newHasher().putBytes(new byte[] { b1, b2, b3 }).hash()
 * }
 *
 * <p>If you wish to avoid this, you should either prepend or append the size of each chunk. Keep in
 * mind that when dealing with char sequences, the encoded form of two concatenated char sequences
 * is not equivalent to the concatenation of their encoded form. Therefore, {@link

        #
        # NB: a `for` loop captures its iteration list before it begins, so
        # changing the positional parameters here affects neither the number of
        # iterations, nor the values presented in `arg`.
        shift                   # remove old arg
        set -- "$@" "$arg"      # push replacement arg
    done
fi

}

func (data EncryptedData) Value() (driver.Value, error) {
	if len(data) > 0 && data[0] == 'x' {
		// needed to test failures
		return nil, errors.New("Should not start with 'x'")
	}

	// prepend asterisks
	return append([]byte("***"), data...), nil
}

type Num int64

func (i *Num) Scan(src interface{}) error {
	switch s := src.(type) {
	case []byte:
		n, _ := strconv.Atoi(string(s))

to sign user certificates for authentication.

Implementation is identical with "TrustedUserCAKeys" setting in OpenSSH server with exception that only one CA
key can be defined.

If a certificate is presented for authentication and has its signing CA key is in this file, then it may be
used for authentication for any user listed in the certificate's principals list. 

            unverifiedHandshake.peerCertificates,
            address.url.host,
          )
        }
      this.handshake = handshake

      // Check that the certificate pinner is satisfied by the certificates presented.
      certificatePinner.check(address.url.host) {
        handshake.peerCertificates.map { it as X509Certificate }
      }

      // Success! Save the handshake and the ALPN protocol.
      val maybeProtocol =