docs: private void setResponseHeader(final RequestContext context) {
          val credential = WebUtils.getCredential(context);
  
          if (credential == null) {
              LOGGER.debug("No credential was provided. No response header set.");
              return;
          }
  
          val response = WebUtils.getHttpServletResponseFromExternalWebflowContext(context);
          val spnegoCredentials = (SpnegoCredential) credential;
          val nextToken = spnegoCredentials.getNextToken();
          if (nextToken != null) {
              LOGGER.debug("Obtained output token: [{}]", new String(nextToken, Charset.defaultCharset()));
              response.setHeader(SpnegoConstants.HEADER_AUTHENTICATE, (this.ntlm
                  ? SpnegoConstants.NTLM : SpnegoConstants.NEGOTIATE)
                  + ' ' + EncodingUtils.encodeBase64(nextToken));
          } else {
              LOGGER.debug("Unable to obtain the output token required.");
          }
  
          if (spnegoCredentials.getPrincipal() == null && this.send401OnAuthenticationFailure) {
              LOGGER.debug("Setting HTTP Status to 401");
              response.setStatus(HttpServletResponse.SC_UNAUTHORIZED);
          }
      }