code: func ResizeInstanceGroup(asg ASG, instanceGroupName string, size int) error {
  	request := &autoscaling.UpdateAutoScalingGroupInput{
  		AutoScalingGroupName: aws.String(instanceGroupName),
  		MinSize:              aws.Int64(int64(size)),
  		MaxSize:              aws.Int64(int64(size)),
  	}
  	if _, err := asg.UpdateAutoScalingGroup(request); err != nil {
  		return fmt.Errorf("error resizing AWS autoscaling group: %q", err)
  	}
  	return nil
  }
docs: // ResizeInstanceGroup sets the size of the specificed instancegroup Exported
  // so it can be used by the e2e tests, which don't want to instantiate a full
  // cloudprovider.