code: private HttpResponse handleCorsPreflight(ServiceRequestContext ctx, HttpRequest req) {
          final HttpHeaders headers = HttpHeaders.of(HttpStatus.OK);
          final CorsPolicy policy = setCorsOrigin(ctx, req, headers);
          if (policy != null) {
              policy.setCorsAllowMethods(headers);
              policy.setCorsAllowHeaders(headers);
              policy.setCorsAllowCredentials(headers);
              policy.setCorsMaxAge(headers);
              policy.setCorsPreflightResponseHeaders(headers);
          }
  
          return HttpResponse.of(headers);
      }
docs: Handles CORS preflight by setting the appropriate headers.
  
  @param req the decoded HTTP request