//                                                                           =========
    private static final RoleTypeDbm _instance = new RoleTypeDbm();

    private RoleTypeDbm() {
    }

    public static RoleTypeDbm getInstance() {
        return _instance;
    }

    // ===================================================================================

    //                                                                           =========
    private static final CrawlingInfoDbm _instance = new CrawlingInfoDbm();

    private CrawlingInfoDbm() {
    }

    public static CrawlingInfoDbm getInstance() {
        return _instance;
    }

    // ===================================================================================

    //                                                                           =========
    private static final JobLogDbm _instance = new JobLogDbm();

    private JobLogDbm() {
    }

    public static JobLogDbm getInstance() {
        return _instance;
    }

    // ===================================================================================

    //                                                                           =========
    private static final FavoriteLogDbm _instance = new FavoriteLogDbm();

    private FavoriteLogDbm() {
    }

    public static FavoriteLogDbm getInstance() {
        return _instance;
    }

    // ===================================================================================

    //                                                                           =========
    private static final ThumbnailQueueDbm _instance = new ThumbnailQueueDbm();

    private ThumbnailQueueDbm() {
    }

    public static ThumbnailQueueDbm getInstance() {
        return _instance;
    }

    // ===================================================================================

    //                                                                           =========
    private static final PathMappingDbm _instance = new PathMappingDbm();

    private PathMappingDbm() {
    }

    public static PathMappingDbm getInstance() {
        return _instance;
    }

    // ===================================================================================

    //                                                                           =========
    private static final FileAuthenticationDbm _instance = new FileAuthenticationDbm();

    private FileAuthenticationDbm() {
    }

    public static FileAuthenticationDbm getInstance() {
        return _instance;
    }

    // ===================================================================================

   */
  fun <T : ConnectionEvent> removeUpToEvent(eventClass: Class<T>): T {
    val fullEventSequence = eventSequence.toList()
    try {
      while (true) {
        val event = takeEvent()
        if (eventClass.isInstance(event)) {
          return eventClass.cast(event)
        }
      }
    } catch (e: NoSuchElementException) {
      throw AssertionError("full event sequence: $fullEventSequence", e)
    }
  }

  /**

    //                                                                           =========
    private static final FailureUrlDbm _instance = new FailureUrlDbm();

    private FailureUrlDbm() {
    }

    public static FailureUrlDbm getInstance() {
        return _instance;
    }

    // ===================================================================================

    //                                                                           =========
    private static final LabelTypeDbm _instance = new LabelTypeDbm();

    private LabelTypeDbm() {
    }

    public static LabelTypeDbm getInstance() {
        return _instance;
    }

    // ===================================================================================