private Callback<String> idConverterCallback() {
      return buildCallback(metrics.undeleteBlobIdConversionMetrics, convertedBlobId -> {
        BlobId blobId = FrontendUtils.getBlobIdFromString(convertedBlobId, clusterMap);
        accountAndContainerInjector.injectTargetAccountAndContainerFromBlobId(blobId, restRequest,
            metrics.undeleteBlobMetricsGroup);
        securityService.postProcessRequest(restRequest, securityPostProcessRequestCallback(blobId));
      }, restRequest.getUri(), LOGGER, finalCallback);
    }
After {@link IdConverter#convert} finishes, call {@link SecurityService#postProcessRequest} to perform
request time security checks that rely on the request being fully parsed and any additional arguments set.
@return a {@link Callback} to be used with {@link IdConverter#convert}.
ambry-frontend/src/main/java/com/github/ambry/frontend/UndeleteHandler.java