acknowledge method
Acknowledges the messages associated with the ack_ids in the
AcknowledgeRequest.
The Pub/Sub system can remove the relevant messages from the subscription. Acknowledging a message whose ack deadline has expired may succeed, but such a message may be redelivered later. Acknowledging a message more than once will not result in an error.
request - The metadata request object.
Request parameters:
subscription - Required. The subscription whose message is being
acknowledged. Format is projects/{project}/subscriptions/{sub}.
Value must have pattern ^projects/\[^/\]+/subscriptions/\[^/\]+$.
$fields - Selector specifying which fields to include in a partial
response.
Completes with a Empty.
Completes with a commons.ApiRequestError if the API endpoint returned an error.
If the used http.Client completes with an error when making a REST call,
this method will complete with the same error.
Implementation
async.Future<Empty> acknowledge(
  AcknowledgeRequest request,
  core.String subscription, {
  core.String? $fields,
}) async {
  final body_ = convert.json.encode(request);
  final queryParams_ = <core.String, core.List<core.String>>{
    if ($fields != null) 'fields': [$fields],
  };
  final url_ = 'v1/' + core.Uri.encodeFull('$subscription') + ':acknowledge';
  final response_ = await _requester.request(
    url_,
    'POST',
    body: body_,
    queryParams: queryParams_,
  );
  return Empty.fromJson(response_ as core.Map<core.String, core.dynamic>);
}