* {@code
     * String username = f.getPrincipal().getName();
     * }
     * The {@code Principal} object returned will never be {@code null}
     * however the username can be {@code null} indication anonymous
     * credentials were used (e.g. some IPC$ services).
     */

    /**
     * Returns the principal used for authentication
     *
     * @return the authentication principal
     */

    This helps prevent "split brain" scenarios in clustered applications by
    ensuring that unreachable pods will not be presumed dead unless some
    "fencing" operation has provided one of the above indications.
  * For all other existing controllers except StatefulSet, this has no effect on
    the ability of the controller to replace pods because the controllers do not
    reuse pod names (they use generate-name).