def store_csrf_tokens(response)
      if response && response.headers
        tokens = response.headers.select { |k, v| %w(csrf csrf_ts).include?(k) }
        if tokens && !tokens.empty?
          @csrf_tokens = tokens
        end
      end
    end
def store_csrf_tokens(response)
      if response && response.headers
        tokens = response.headers.select { |k, v| %w(csrf csrf_ts).include?(k) }
        if tokens && !tokens.empty?
          @csrf_tokens = tokens
        end
      end
    end
Is called from `parse_response` to store the latest csrf_token (if available)