///

## Dataclasses in `response_model`

You can also use `dataclasses` in the `response_model` parameter:

{* ../../docs_src/dataclasses/tutorial002.py hl[1,7:13,19] *}

The dataclass will be automatically converted to a Pydantic dataclass.

This way, its schema will show up in the API docs user interface:

<img src="/img/tutorial/dataclasses/image01.png">

## Dataclasses in Nested Data Structures

   *
   * <p><b>Warning:</b> please see {@link Short#decode} to understand exactly how strings are
   * parsed. For example, the string {@code "0123"} is treated as <i>octal</i> and converted to the
   * value {@code 83}.
   *
   * @since 16.0
   */
  public static Converter<String, Short> stringConverter() {
    return ShortConverter.INSTANCE;
  }

  /**

   *
   * <p><b>Warning:</b> please see {@link Short#decode} to understand exactly how strings are
   * parsed. For example, the string {@code "0123"} is treated as <i>octal</i> and converted to the
   * value {@code 83}.
   *
   * @since 16.0
   */
  public static Converter<String, Short> stringConverter() {
    return ShortConverter.INSTANCE;
  }

  /**

     * from the runtime environment like {@link System#getProperties()} and environment variables.
     *
     * @return The system properties, never {@code null}.
     */
    Properties getSystemProperties();

    /**
     * Sets the system properties to use for interpolation and profile activation. The system properties are collected

   * an IPv4 address or not.
   *
   * <p>IPv6 addresses are <b>coerced</b> to IPv4 addresses before being converted to integers.
   *
   * <p>As long as there are applications that assume that all IP addresses are IPv4 addresses and
   * can therefore be converted safely to integers (for whatever purpose) this function can be used
   * to handle IPv6 addresses as well until the application is suitably fixed.

          }
        });
  }

  public void testContainsKeyAndValue() {
    for (LoadingCache<Key, String> cache : caches()) {
      // maintain strong refs so these won't be collected, regardless of cache's key/value strength
      Key key = new Key(1);
      String value = key.toString();
      assertSame(value, cache.getUnchecked(key));
      assertTrue(cache.asMap().containsKey(key));

		Transport:   transport,
		CloseRespFn: closeRespFn,
	}
	if err = args.Validate(); err != nil {
		return args, err
	}
	return args, nil
}

// New - initializes opa policy engine connector.
func New(args Args) *Opa {
	// No opa args.
	if args.URL == nil || args.URL.Scheme == "" && args.AuthToken == "" {
		return nil
	}
	return &Opa{
		args:   args,

## Known Issues

- There is a known issue [coredns/coredns#2629](https://github.com/coredns/coredns/issues/2629) in CoreDNS 1.3.1, wherein if the Kubernetes API shuts down while CoreDNS is connected, CoreDNS will crash. The issue is fixed in CoreDNS 1.4.0 in [coredns/coredns#2529](https://github.com/coredns/coredns/pull/2529).

But if you return a `Response` directly (or any subclass, like `JSONResponse`), the data won't be automatically converted (even if you declare a `response_model`), and the documentation won't be automatically generated (for example, including the specific "media type", in the HTTP header `Content-Type` as part of the generated OpenAPI).

      call.execute()
    }

    // Observed Events are variable
    // JDK 14
    // CallStart, ProxySelectStart, ProxySelectEnd, DnsStart, DnsEnd, ConnectStart, SecureConnectStart,
    // SecureConnectEnd, ConnectEnd, ConnectionAcquired, RequestHeadersStart, RequestHeadersEnd,
    // ResponseFailed, ConnectionReleased, CallFailed
    // JDK 8