*/
package okhttp3.internal

import java.net.InetAddress
import okhttp3.Dns

/**
 * A network that always resolves two IP addresses per host. Use this when testing route selection
 * fallbacks to guarantee that a fallback address is available.
 */
class DoubleInetAddressDns : Dns {
  override fun lookup(hostname: String): List<InetAddress> {
    val addresses = Dns.SYSTEM.lookup(hostname)

      )

    client =
      clientTestRule.newClientBuilder()
        .eventListenerFactory(clientTestRule.wrap(listener))
        .connectTimeout(60, TimeUnit.SECONDS) // Deliberately exacerbate slow fallbacks.
        .dns { dnsResults }
        .fastFallback(true)
        .build()
    url =
      serverIpv4.url("/")
        .newBuilder()
        .host("localhost")
        .build()
  }

    return connectionListener.recordedEventTypes()
  }

  companion object {
    /**
     * A network that resolves only one IP address per host. Use this when testing route selection
     * fallbacks to prevent the host machine's various IP addresses from interfering.
     */
    private val SINGLE_INET_ADDRESS_DNS =
      Dns { hostname ->
        val addresses = Dns.SYSTEM.lookup(hostname)

            </signature>
            <ignores>
              <!-- Unsafe isn't part of the documented Android API, but it is available.
                   And in cases where it's not, we have fallbacks (except maybe Striped64 (b/307807965)?). -->
              <ignore>sun.misc.Unsafe</ignore>
            </ignores>
          </configuration>
          <executions>
            <execution>

                        "501": {"description": "Server error level 1"},
                    },
                    "callbacks": {
                        "callback0": {
                            "/": {
                                "get": {
                                    "summary": "Callback0",
                                    "operationId": "callback0__get",
                                    "parameters": [

	var callbacks []*callback
	removedMap := map[string]bool{}
	for _, callback := range p.callbacks {
		if callback.match == nil || callback.match(p.db) {
			callbacks = append(callbacks, callback)
		}
		if callback.remove {
			removedMap[callback.name] = true
		}
	}

	if len(removedMap) > 0 {
		callbacks = removeCallbacks(callbacks, removedMap)
	}
	p.callbacks = callbacks

    server.protocolNegotiationEnabled = true
    server.protocols = client.protocols
  }

  /**
   * Used during tests that involve TLS connection fallback attempts. OkHttp includes the
   * TLS_FALLBACK_SCSV cipher on fallback connections. See [FallbackTestClientSocketFactory]
   * for details.
   */

    fun retryOnConnectionFailure(retryOnConnectionFailure: Boolean) =
      apply {
        this.retryOnConnectionFailure = retryOnConnectionFailure
      }

    /**
     * Configure this client to perform fast fallbacks by attempting multiple connections
     * concurrently, returning once any connection connects successfully.
     *
     * This implements Happy Eyeballs ([RFC 6555][rfc_6555]), balancing connect latency vs.

///

### Einen Callback-`APIRouter` erstellen

Erstellen Sie zunächst einen neuen `APIRouter`, der einen oder mehrere Callbacks enthält.

```Python hl_lines="3  25"
{!../../docs_src/openapi_callbacks/tutorial001.py!}
```

### Die Callback-*Pfadoperation* erstellen

///

### Create a callback `APIRouter`

First create a new `APIRouter` that will contain one or more callbacks.

```Python hl_lines="3  25"
{!../../docs_src/openapi_callbacks/tutorial001.py!}
```

### Create the callback *path operation*

To create the callback *path operation* use the same `APIRouter` you created above.

It should look just like a normal FastAPI *path operation*: