private Optional<LocalSession> getOptionalSessionFromFileSystem(long sessionId) {
        try {
            return Optional.of(getSessionFromFile(sessionId));
        } catch (Exception e) {
            log.log(Level.FINE, () -> "could not get session from file: " + sessionId + ": " + e.getMessage());
        }
        return Optional.empty();
    }
A session for which we don't have a watcher, i.e. hitherto unknown to us.

@param sessionId session id for the new session
configserver/src/main/java/com/yahoo/vespa/config/server/session/SessionRepository.java