code: public PubsubFuture<Void> modifyAckDeadline(final String project, final String subscription,
                                                final int ackDeadlineSeconds, final String... ackIds) {
      return modifyAckDeadline(project, subscription, ackDeadlineSeconds, asList(ackIds));
    }
docs: Modify the ack deadline for a list of received messages.
  
  @param project            The Google Cloud project.
  @param subscription       The subscription of the received message to modify the ack deadline on.
  @param ackDeadlineSeconds The new ack deadline.
  @param ackIds             List of message ID's to modify the ack deadline on.
  @return A future that is completed when this request is completed.