* wish to override {@code subMap} to forward to this implementation.
   */
  @Override
  protected SortedMap<K, V> standardSubMap(
      @ParametricNullness K fromKey, @ParametricNullness K toKey) {
    return subMap(fromKey, true, toKey, false);
  }

  @Override
  public NavigableMap<K, V> subMap(
      @ParametricNullness K fromKey,
      boolean fromInclusive,

    private final Object mutex = new Object[0]; // something Serializable

    @Override
    public boolean offer(E o) {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.offer(o);
    }

    @Override
    public @Nullable E poll() {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.poll();
    }

    @Override
    public E remove() {
      assertTrue(Thread.holdsLock(mutex));

  }

  private interface Equals {
    @Override
    boolean equals(@Nullable Object obj);

    @Override
    int hashCode();

    @Override
    String toString();
  }

  private static class NoDelegateToEquals implements Equals {

    private static final Function<Equals, Equals> WRAPPER =
        new Function<Equals, Equals>() {
          @Override

    }

    @Override
    boolean isLessThan(Comparable<?> value) {
      return true;
    }

    @Override
    BoundType typeAsLowerBound() {
      throw new IllegalStateException();
    }

    @Override
    BoundType typeAsUpperBound() {
      throw new AssertionError("this statement should be unreachable");
    }

    @Override
    Cut<Comparable<?>> withLowerBoundType(

  }

  @Override
  public NavigableSet<K> navigableKeySet() {
    return new Maps.NavigableKeySet<>(this);
  }

  @Override
  public Set<K> keySet() {
    return navigableKeySet();
  }

  @Override
  public NavigableSet<K> descendingKeySet() {
    return descendingMap().navigableKeySet();
  }

  @Override
  public NavigableMap<K, V> descendingMap() {
    return new DescendingMap();
  }

    }

    @Override
    public @Nullable V ceiling(@ParametricNullness V v) {
      return getSortedSetDelegate().ceiling(v);
    }

    @Override
    public @Nullable V higher(@ParametricNullness V v) {
      return getSortedSetDelegate().higher(v);
    }

    @Override
    public @Nullable V pollFirst() {
      return Iterators.pollNext(iterator());
    }

    @Override

    }

    @Nonnull
    @Override
    public String getGroupId() {
        return project.getGroupId();
    }

    @Nonnull
    @Override
    public String getArtifactId() {
        return project.getArtifactId();
    }

    @Nonnull
    @Override
    public String getVersion() {
        return project.getVersion();
    }

    @Nonnull
    @Override

    @Override
    public String toString() {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.toString();
    }

    @Override
    public boolean equals(@Nullable Object o) {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.equals(o);
    }

    @Override
    public int hashCode() {
      assertTrue(Thread.holdsLock(mutex));

  /** Constructor for use by subclasses. */
  protected ForwardingMap() {}

  @Override
  protected abstract Map<K, V> delegate();

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

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

  @CanIgnoreReturnValue
  @Override
  public @Nullable V remove(@Nullable Object key) {
    return delegate().remove(key);
  }

  /** Constructor for use by subclasses. */
  protected ForwardingMultimap() {}

  @Override
  protected abstract Multimap<K, V> delegate();

  @Override
  public Map<K, Collection<V>> asMap() {
    return delegate().asMap();
  }

  @Override
  public void clear() {
    delegate().clear();
  }

  @Override
  public boolean containsEntry(@Nullable Object key, @Nullable Object value) {