abstract Iterator<Entry<K, V>> entryIterator();

  Spliterator<Entry<K, V>> entrySpliterator() {
    return Spliterators.spliterator(
        entryIterator(), size(), (this instanceof SetMultimap) ? Spliterator.DISTINCT : 0);
  }

  @LazyInit private transient @Nullable Set<K> keySet;

  @Override
  public Set<K> keySet() {
    Set<K> result = keySet;
    return (result == null) ? keySet = createKeySet() : result;

    if (needsAllocArrays()) {
      return Spliterators.spliterator(new Object[0], Spliterator.DISTINCT | Spliterator.ORDERED);
    }
    Set<E> delegate = delegateOrNull();
    return (delegate != null)
        ? delegate.spliterator()
        : Spliterators.spliterator(
            requireElements(), 0, size, Spliterator.DISTINCT | Spliterator.ORDERED);
  }

  @Override
  public void forEach(Consumer<? super E> action) {

            if (i > 0 && comparator.compare((K) sortedKeys[i - 1], (K) sortedKeys[i]) == 0) {
              throw new IllegalArgumentException(
                  "keys required to be distinct but compared as equal: "
                      + sortedKeys[i - 1]
                      + " and "
                      + sortedKeys[i]);
            }

                0,
                (Entry<C, V> columnEntry) ->
                    immutableCell(rowEntry.getKey(), columnEntry.getKey(), columnEntry.getValue())),
        Spliterator.DISTINCT | Spliterator.SIZED | Spliterator.NONNULL,
        size());
  }

  @Override
  public Map<C, V> row(R rowKey) {
    return new Row(rowKey);
  }

  class Row extends IteratorBasedAbstractMap<C, V> {

      };
    }

    @Override
    @GwtIncompatible // Spliterator
    Spliterator<Entry<K, V>> entrySpliterator() {
      return CollectSpliterators.indexed(
          size(), Spliterator.ORDERED | Spliterator.DISTINCT | Spliterator.NONNULL, this::getEntry);
    }

    // TODO(lowasser): consider an optimized values() implementation

    @Override
    public boolean containsKey(@Nullable Object key) {

    @Override
    @GwtIncompatible // Spliterator
    Spliterator<Cell<C, R, V>> cellSpliterator() {
      return CollectSpliterators.map(
          original.cellSet().spliterator(),
          Spliterator.DISTINCT | Spliterator.NONNULL,
          Tables::transposeCell);
    }
  }

  private static <
          R extends @Nullable Object, C extends @Nullable Object, V extends @Nullable Object>

   * loading the value for this key, simply waits for that thread to finish and returns its loaded
   * value. Note that multiple threads can concurrently load values for distinct keys.
   *
   * <p>This method does not alter the state of this {@code CacheBuilder} instance, so it can be
   * invoked again to create multiple independent caches.
   *

//  fn_name - the name of the new TF_Function. Should match the operation
//            name (OpDef.name) regexp [A-Z][A-Za-z0-9_.\\-/]*.
//            If `append_hash_to_fn_name` is false, `fn_name` must be distinct
//            from other function and operation names (at least those
//            registered in graphs where this function will be used).
//  append_hash_to_fn_name - Must be 0 or 1. If set to 1, the actual name

        return fromSpliterator.getComparator();
      }

      @Override
      public int characteristics() {
        return fromSpliterator.characteristics()
            & (Spliterator.DISTINCT
                | Spliterator.NONNULL
                | Spliterator.ORDERED
                | Spliterator.SORTED);
      }
    }
    return new Splitr();
  }

  /**

    @GwtIncompatible // Spliterator
    Spliterator<Entry<K, V>> entrySpliterator() {
      return Spliterators.spliterator(
          entryIterator(),
          size(),
          Spliterator.DISTINCT | Spliterator.NONNULL | Spliterator.IMMUTABLE | Spliterator.ORDERED);
    }

    @Override
    ImmutableSet<K> createKeySet() {
      return new ImmutableMapKeySet<>(this);
    }

    @Override