private static DataplaneToken.Version tokenValue(Inspector inspector) {
        String expirationStr = inspector.field(EXPIRATION_FIELD).asString();
        return new DataplaneToken.Version(
                inspector.field(FINGERPRINT_FIELD).asString(),
                inspector.field(CHECKACCESSHASH_FIELD).asString(),
                expirationStr.equals("<none>") ? Optional.empty()
                        : (expirationStr.isBlank()
                        ? Optional.of(Instant.EPOCH) : Optional.of(Instant.parse(expirationStr))));
    }
Serialize/deserialize dataplane tokens

@author mortent
configserver/src/main/java/com/yahoo/vespa/config/server/tenant/DataplaneTokenSerializer.java