def sign_request(request)
      super(request)

      if (request.respond_to?(:request_headers))
        request.request_headers['aeg-sas-key'] = @topic_key
      elsif request.respond_to?(:headers)
        request.headers['aeg-sas-key'] = @topic_key
      else
        fail ArgumentError, 'Incorrect request object was provided'
      end
    end
def sign_request(request)
      super(request)

      if (request.respond_to?(:request_headers))
        request.request_headers['aeg-sas-key'] = @topic_key
      elsif request.respond_to?(:headers)
        request.headers['aeg-sas-key'] = @topic_key
      else
        fail ArgumentError, 'Incorrect request object was provided'
      end
    end
Creates and initialize new instance of the TopicCredentials class.
 @param topic_key [String] topic key