private void ValidateTopicByName(RoutingKey topic)
 {
     using (var snsClient = new AmazonSimpleNotificationServiceClient(_awsConnection.Credentials, _awsConnection.Region))
     {
         var(success, arn) = FindTopicByName(topic.ToValidSNSTopicName(), snsClient);
         if (success)
         {
             _channelTopicArn = arn;
         }
         else
         {
             throw new BrokerUnreachableException(
                       $"Topic validation error: could not find topic {topic.ToValidSNSTopicName()}. Did you want Brighter to create infrastructure?");
         }
     }
 }