default String getUserIdentityForAudit() {
        final UserIdentity userIdentity = getUserIdentity();
        if (userIdentity == null) {
            return null;
        }
        return userIdentity.getUserIdentityForAudit();
    }
@return The user identity in a form suitable for use in audit events, for display
in the UI, or in exception messages. Returns {@link UserIdentity#getDisplayName()} or
if that is not set {@link UserIdentity#getSubjectId()}.
stroom-security/stroom-security-api/src/main/java/stroom/security/api/SecurityContext.java