}

    @Override
    public boolean isEmpty() {
      synchronized (mutex) {
        return delegate().isEmpty();
      }
    }

    @Override
    public Iterator<E> iterator() {
      return delegate().iterator(); // manually synchronized
    }

    @Override
    public Spliterator<E> spliterator() {
      synchronized (mutex) {
        return delegate().spliterator();
      }
    }

    this.delegate = delegate;
    checkArgument(!delegate.isEmpty());
  }

  @Override
  UnmodifiableIterator<K> keyIterator() {
    return Iterators.unmodifiableIterator(delegate.keySet().iterator());
  }

  @Override
  public int size() {
    return delegate.size();
  }

  @Override
  public boolean containsKey(@Nullable Object key) {
    return delegate.containsKey(key);
  }

   * contains(). Verify that these sets are consistent with the elements of their iterator.
   */
  @CanIgnoreReturnValue
  static <T> Set<T> sanityCheckSet(Set<T> set) {
    assertThat(set).hasSize(Iterators.size(set.iterator()));
    for (Object element : set) {
      assertThat(set).contains(element);
    }
    assertThat(set).doesNotContain(new Object());

                          public long skip(long n) {
                            return 0;
                          }
                        };
                      }
                    })
                .iterator());
    assertEquals(0, multi.skip(-1));
    assertEquals(0, multi.skip(-1));
    assertEquals(0, multi.skip(0));
    ByteStreams.skipFully(multi, 20);
    assertEquals(20, multi.read());
  }

    Multiset<Multiset<?>> multiset = HashMultiset.create();
    multiset.add(multiset, 2);
    Multiset<Multiset<?>> copy = SerializableTester.reserialize(multiset);
    assertEquals(2, copy.size());
    assertSame(copy, copy.iterator().next());
  }

  @J2ktIncompatible
  @GwtIncompatible // Only used by @GwtIncompatible code
  private static class MultisetHolder implements Serializable {
    private final Multiset<?> member;

    int copyIntoArray(@Nullable Object[] dst, int offset) {
      return entries.copyIntoArray(dst, offset);
    }

    @Override
    public UnmodifiableIterator<Entry<K, V>> iterator() {
      return entries.iterator();
    }

    @Override
    @GwtIncompatible("Spliterator")
    public Spliterator<Entry<K, V>> spliterator() {
      return entries.spliteratorWithCharacteristics(SPLITERATOR_CHARACTERISTICS);

        CloseableUtil.closeQuietly(in);

        final String content = extractData.getContent();
        logger.info("Without header: " + content);

        // All lines should be treated as data
        assertTrue(content.contains("Name"));
        assertTrue(content.contains("John Doe"));
    }

    public void test_getText_withoutColumnMetadata() {

    #    member name : The name of member's full name
    #  you can use the alias in DBFlute world, java-doc, SchemaHTML...
    #  DB comment which does not have the delimiter is not treated
    #  as alias, treated as description (real comment).
    #  But you can change it by 'isDbCommentOnAliasBasis'.
    #
    #; aliasDelimiterInDbComment = :
    # - - - - - - - - - -/

  }

  protected K getKeyForNullValue() {
    return getEntryNullReplaces().getKey();
  }

  private Entry<K, V> getEntryNullReplaces() {
    Iterator<Entry<K, V>> entries = getSampleElements().iterator();
    for (int i = 0; i < getNullLocation(); i++) {
      entries.next();
    }
    return entries.next();
  }

  /**

  ImmutableMapKeySet(ImmutableMap<K, V> map) {
    this.map = map;
  }

  @Override
  public int size() {
    return map.size();
  }

  @Override
  public UnmodifiableIterator<K> iterator() {
    return map.keyIterator();
  }

  @Override
  public boolean contains(@Nullable Object object) {
    return map.containsKey(object);
  }

  @Override
  K get(int index) {