*
   * @since 20.0
   */
  public static void throwIfUnchecked(Throwable throwable) {
    checkNotNull(throwable);
    if (throwable instanceof RuntimeException) {
      throw (RuntimeException) throwable;
    }
    if (throwable instanceof Error) {
      throw (Error) throwable;
    }
  }

  /**
   * Propagates {@code throwable} exactly as-is, if and only if it is an instance of {@link

    @Override
    public void suppress(Closeable closeable, Throwable thrown, Throwable suppressed) {
      suppressions.add(new Suppression(closeable, thrown, suppressed));
    }
  }

  /** Record of a call to suppress. */
  private static class Suppression {
    private final Closeable closeable;
    private final Throwable thrown;
    private final Throwable suppressed;

    @Override
    public void suppress(Closeable closeable, Throwable thrown, Throwable suppressed) {
      suppressions.add(new Suppression(closeable, thrown, suppressed));
    }
  }

  /** Record of a call to suppress. */
  private static class Suppression {
    private final Closeable closeable;
    private final Throwable thrown;
    private final Throwable suppressed;

    /**
     * Creates a new MultipleCrawlingAccessException with the specified detail message and array of throwables.
     *
     * @param message the detail message explaining the reason for the exception
     * @param throwables the array of throwables that caused this exception
     */
    public MultipleCrawlingAccessException(final String message, final Throwable[] throwables) {
        super(message);

    Throwable throwable = thrown;

    // close closeables in LIFO order
    while (!stack.isEmpty()) {
      Closeable closeable = stack.removeFirst();
      try {
        closeable.close();
      } catch (Throwable e) {
        if (throwable == null) {
          throwable = e;
        } else {
          suppressor.suppress(closeable, throwable, e);
        }
      }
    }

  static void assertNodeNotInGraphErrorMessage(Throwable throwable) {
    assertThat(throwable).hasMessageThat().startsWith(NODE_STRING);
    assertThat(throwable).hasMessageThat().contains(ERROR_ELEMENT_NOT_IN_GRAPH);
  }

  static void assertEdgeNotInGraphErrorMessage(Throwable throwable) {
    assertThat(throwable).hasMessageThat().startsWith(EDGE_STRING);
    assertThat(throwable).hasMessageThat().contains(ERROR_ELEMENT_NOT_IN_GRAPH);
  }

        setMdc();
        logger.warn(message, throwable);
    }

    @Override
    public boolean isWarnEnabled() {
        return logger.isWarnEnabled();
    }

    @Override
    public void error(String message) {
        setMdc();
        logger.error(message);
    }

    @Override
    public void error(String message, Throwable throwable) {
        setMdc();

    }

    /**
     * Outputs a log entry.
     *
     * @param throwable
     *            Exception. Must not be {@literal null}.
     */
    public void log(final Throwable throwable) {
        assertArgumentNotNull("throwable", throwable);

        error(throwable.getMessage(), throwable);
    }

    /**
     * Outputs a log entry.
     *
     * @param messageCode

    ImmutableMap<Class<? extends Throwable>, Predicate<Throwable>> exceptions() {
      return ImmutableMap.of();
    }
  }

  private static final ImmutableMap<Class<? extends Throwable>, Predicate<Throwable>> INSTANCE_OF =
      ImmutableMap.<Class<? extends Throwable>, Predicate<Throwable>>builder()
          .put(ArithmeticException.class, e -> e instanceof ArithmeticException)

        // nothing
    }

    /**
     * A list of Throwables representing failures that occurred during the operation.
     */
    protected List<Throwable> failures = Collections.synchronizedList(new ArrayList<>());

    /**
     * Adds a Throwable to the list of failures.
     *
     * @param t the Throwable to add
     */
    public void addFailure(final Throwable t) {
        failures.add(t);
    }

    /**