public int[] batchInsert(List<RequestHeader> list, RequestOptionCall<BulkRequestBuilder> call) {
        return batchInsert(list, call, null);
    }

    public int[] batchInsert(List<RequestHeader> list, RequestOptionCall<BulkRequestBuilder> call,
            RequestOptionCall<IndexRequestBuilder> entityCall) {
        return doBatchInsert(new BulkList<>(list, call, entityCall), null);
    }

    public int[] batchInsert(List<ThumbnailQueue> list, RequestOptionCall<BulkRequestBuilder> call) {
        return batchInsert(list, call, null);
    }

    public int[] batchInsert(List<ThumbnailQueue> list, RequestOptionCall<BulkRequestBuilder> call,
            RequestOptionCall<IndexRequestBuilder> entityCall) {
        return doBatchInsert(new BulkList<>(list, call, entityCall), null);
    }

        .build()
    val latch = CountDownLatch(1)
    val exceptionRef = AtomicReference<Throwable>()
    val call = client.newCall(request)
    call.timeout().timeout(250, TimeUnit.MILLISECONDS)
    call.enqueue(
      object : Callback {
        override fun onFailure(
          call: Call,
          e: IOException,
        ) {
          exceptionRef.set(e)
          latch.countDown()
        }

        return batchInsert(list, call, null);
    }

    public int[] batchInsert(List<WebAuthentication> list, RequestOptionCall<BulkRequestBuilder> call,
            RequestOptionCall<IndexRequestBuilder> entityCall) {
        return doBatchInsert(new BulkList<>(list, call, entityCall), null);
    }

      for (PerListenerQueue<L> queue : listeners) {
        queue.add(event, label);
      }
    }
  }

  /**
   * Dispatches all events enqueued prior to this call, serially and in order, for every listener.
   *
   * <p>Note: this method is idempotent and safe to call from any thread
   */
  public void dispatch() {
    // iterate by index to avoid concurrent modification exceptions

      object : Callback {
        override fun onFailure(
          call: Call,
          e: IOException,
        ) {
          continuation.resumeWithException(e)
        }

        override fun onResponse(
          call: Call,
          response: Response,
        ) {
          continuation.resume(response) { _, value, _ ->
            value.closeQuietly()
          }
        }
      },
    )

	return c.call(ctx, lockRPCRLock, &args)
}

// Lock calls lock REST API.
func (c *lockRESTClient) Lock(ctx context.Context, args dsync.LockArgs) (reply bool, err error) {
	return c.call(ctx, lockRPCLock, &args)
}

// RUnlock calls read unlock REST API.
func (c *lockRESTClient) RUnlock(ctx context.Context, args dsync.LockArgs) (reply bool, err error) {
	return c.call(ctx, lockRPCRUnlock, &args)
}

An example could be that you have an external authentication provider that you need to call.

You send it a token and it returns an authenticated user.

This provider might be charging you per request, and calling it might take some extra time than if you had a fixed mock user for tests.

You probably want to test the external provider once, but not necessarily call it for every test that runs.

 *
 * Each instance processes a single event on [call], and then adds a successor [EventListenerRelay]
 * on the same [call] to process the next event.
 *
 * By forcing the list of listeners to change after every event, we can detect if buggy code caches
 * a stale [EventListener] in a field or local variable.
 */
class EventListenerRelay(
  val call: Call,
  val eventRecorder: EventRecorder,
) {

        if self.call is None:
            return False  # pragma: no cover
        if inspect.isgeneratorfunction(
            _impartial(self.call)
        ) or inspect.isgeneratorfunction(_unwrapped_call(self.call)):
            return True
        if inspect.isclass(_unwrapped_call(self.call)):
            return False
        dunder_call = getattr(_impartial(self.call), "__call__", None)  # noqa: B004