}
      }
    ```

### Asynchronous Get ([.kt][AsynchronousGetKotlin], [.java][AsynchronousGetJava])

Download a file on a worker thread, and get called back when the response is readable. The callback is made after the response headers are ready. Reading the response body may still block. OkHttp doesn't currently offer asynchronous APIs to receive a response body in parts.

=== ":material-language-kotlin: Kotlin"
    ```kotlin

   * across calls to multiple listeners. Specifically, a given listener will have its callbacks
   * invoked in the same order as the underlying service enters those states. Additionally, at most
   * one of the listener's callbacks will execute at once. However, multiple listeners' callbacks
   * may execute concurrently, and listeners may execute in an order different from the one in which
   * they were registered.

import java.net.SocketTimeoutException
import java.util.ArrayDeque
import java.util.Random
import java.util.concurrent.TimeUnit
import java.util.concurrent.TimeUnit.MILLISECONDS
import okhttp3.Call
import okhttp3.Callback
import okhttp3.EventListener
import okhttp3.OkHttpClient
import okhttp3.Protocol
import okhttp3.Request
import okhttp3.Response
import okhttp3.WebSocket
import okhttp3.WebSocketListener

```

#### 6.2 Implementation Tasks
- [ ] Implement Witness RPC protocol
- [ ] Create witness service discovery
- [ ] Implement client registration
- [ ] Add notification callback mechanism
- [ ] Create resource monitoring
- [ ] Implement automatic re-registration
- [ ] Add cluster node tracking
- [ ] Create failover coordination

#### 6.3 Integration Points

        // Assert
        assertEquals("Status of test-cluster is changed to RED.", result);
        // Note: Notification sending is tested but we don't verify the mock since it uses complex callback mechanism
    }

    // Test state change with empty notification addresses
    @Test
    public void test_execute_stateChangeEmptyNotificationAddresses() {
        // Setup mock components

        ).eventListenerFactory(clientTestRule.wrap(listener1))
        .build()
    val request = Request.Builder().url(sanUrl).build()
    val call1 = client1.newCall(request)
    call1.enqueue(
      object : Callback {
        @Throws(IOException::class)
        override fun onResponse(
          call: Call,
          response: Response,
        ) {
          try {

            accessResult.setStatus(200);
            accessResult.setUrl("http://www.example.com/page" + i);

            dataService.store(accessResult);
        }

        // Test getAccessResultList with callback
        final List<OpenSearchAccessResult> results = dataService.getAccessResultList(builder -> {
            builder.setQuery(QueryBuilders.termQuery("sessionId", sessionId));
            builder.setSize(10);
        });

///

### Crea un `APIRouter` de callback { #create-a-callback-apirouter }

Primero crea un nuevo `APIRouter` que contendrá uno o más callbacks.

{* ../../docs_src/openapi_callbacks/tutorial001_py310.py hl[1,23] *}

### Crea la *path operation* del callback { #create-the-callback-path-operation }

Para crear la *path operation* del callback usa el mismo `APIRouter` que creaste arriba.

///

### Bir callback `APIRouter` oluşturun { #create-a-callback-apirouter }

Önce bir veya daha fazla callback içerecek yeni bir `APIRouter` oluşturun.

{* ../../docs_src/openapi_callbacks/tutorial001_py310.py hl[1,23] *}

### Callback *path operation*'ını oluşturun { #create-the-callback-path-operation }

		return 0, buf, fmt.Errorf("decodeXLHeaders: Negative version count %d", versions)
	}
	return versions, buf, nil
}

// decodeVersions will decode a number of versions from a buffer
// and perform a callback for each version in order, newest first.
// Any non-nil error is returned.
func decodeVersions(buf []byte, versions int, fn func(idx int, hdr, meta []byte) error) (e error) {
	var tHdr, tMeta []byte // Zero copy bytes