public function acknowledge($subscription, $ackIds, $optionalArgs = [])
{
$request = new AcknowledgeRequest();
$request->setSubscription($subscription);
foreach ($ackIds as $elem) {
$request->addAckIds($elem);
}
$mergedSettings = $this->defaultCallSettings['acknowledge']->merge(new CallSettings($optionalArgs));
$callable = ApiCallable::createApiCall($this->subscriberStub, 'Acknowledge', $mergedSettings, $this->descriptors['acknowledge']);
return $callable($request, [], ['call_credentials_callback' => $this->createCredentialsCallback()]);
}