*
   * @throws NullPointerException if the last element is null; if this is a possibility, use {@link
   *     Iterables#getLast} instead.
   */
  @SuppressWarnings("nullness") // Unsafe, but we can't do much about it now.
  public final Optional<@NonNull E> last() {
    // Iterables#getLast was inlined here so we don't have to throw/catch a NSEE

    // TODO(kevinb): Support a concurrently modified collection?

   *
   * @throws NullPointerException if the last element is null; if this is a possibility, use {@link
   *     Iterables#getLast} instead.
   */
  @SuppressWarnings("nullness") // Unsafe, but we can't do much about it now.
  public final Optional<@NonNull E> last() {
    // Iterables#getLast was inlined here so we don't have to throw/catch a NSEE

    // TODO(kevinb): Support a concurrently modified collection?

                n++;
                final int size = chain.size();
                final int cost = chain.getCreditCost();
                final CommonServerMessageBlockRequest next = chain.getNext();
                if (log.isTraceEnabled()) {
                    log.trace(String.format("%s costs %d avail %d (%s)", chain.getClass().getName(), cost, this.credits.availablePermits(),
                            this.name));

        }

        try {
            URL url = new URL(null, smbUrl, new jcifs.smb.Handler());

            // Validate host
            String host = url.getHost();
            if (host == null || host.isEmpty()) {
                throw new SmbException("SMB URL missing host");
            }

            // Validate host format
            if (!isValidHost(host)) {

        this.overrideTimeout = overrideTimeout;
    }

    /**
     *
     * {@inheritDoc}
     *
     * @see jcifs.internal.CommonServerMessageBlockRequest#getNext()
     */
    @Override
    public ServerMessageBlock getNext() {
        return null;
    }

    /**
     * {@inheritDoc}
     *

    protected Object parsePrimitive(final JsonParser jsonParser) throws IOException {
        final JsonToken token = jsonParser.getCurrentToken();
        return switch (token) {
        case VALUE_STRING -> jsonParser.getText();
        case VALUE_NUMBER_INT -> jsonParser.getLongValue();
        case VALUE_NUMBER_FLOAT -> jsonParser.getDoubleValue();
        case VALUE_TRUE -> true;
        case VALUE_FALSE -> false;

        }

        public TestServerMessageBlock2Response(Configuration config, int command) {
            super(config, command);
        }

        @Override
        public ServerMessageBlock2 getNext() {
            return nextBlock;
        }

        @Override
        public void setNext(ServerMessageBlock2 next) {
            this.nextBlock = next;
        }

        void testDefaultRequestProperties() {
            assertEquals(0, testBlock.size());
            assertFalse(testBlock.isAsync());
            assertFalse(testBlock.isResponseAsync());
            assertNull(testBlock.getNext());
            assertFalse(testBlock.allowChain(mock(CommonServerMessageBlockRequest.class)));
            assertNull(testBlock.split());
            assertNull(testBlock.createCancel());

        final byte[] e8 = new byte[8];

        for (int i = 0; i < key.length / 7; i++) {
            System.arraycopy(key, i * 7, key7, 0, 7);
            final Cipher des = Crypto.getDES(key7);
            des.update(data, 0, data.length, e8);
            System.arraycopy(e8, 0, e, i * 8, 8);
        }
    }

   */
  @GwtIncompatible // NavigableSet
  @Override
  public @Nullable E lower(E e) {
    return Iterators.<@Nullable E>getNext(headSet(e, false).descendingIterator(), null);
  }

  /**
   * @since 12.0
   */
  @Override
  public @Nullable E floor(E e) {
    return Iterators.<@Nullable E>getNext(headSet(e, true).descendingIterator(), null);
  }

  /**
   * @since 12.0
   */
  @Override