long originalSize = spliterator.estimateSize();
    GeneralSpliterator<E> trySplit = spliterator.trySplit();
    if (spliterator.estimateSize() > originalSize) {
      fail(
          format(
              "estimated size of spliterator after trySplit (%s) is larger than original size (%s)",
              spliterator.estimateSize(), originalSize));
    }
    if (trySplit != null) {

        return result;
      } else {
        return null;
      }
    }

    @Override
    public final long estimateSize() {
      if (prefix != null) {
        estimatedSize = max(estimatedSize, prefix.estimateSize());
      }
      return max(estimatedSize, 0);
    }

    @Override
    public final int characteristics() {
      return characteristics;
    }
  }

  /**

      Iterable<? extends Entry<? extends K, ? extends V>> entries) {
    int estimatedSize =
        (entries instanceof Collection)
            ? ((Collection<?>) entries).size()
            : ImmutableCollection.Builder.DEFAULT_INITIAL_CAPACITY;
    return new Builder<K, V>(estimatedSize).putAll(entries).build();
  }

  ImmutableBiMap() {}

  /**
   * {@inheritDoc}
   *

   * some amount of padding, it's best if you choose your desired amount explicitly.
   *
   * @param estimatedSize an estimate of the eventual {@link List#size()} of the new list
   * @return a new, empty {@code ArrayList}, sized appropriately to hold the estimated number of
   *     elements
   * @throws IllegalArgumentException if {@code estimatedSize} is negative
   */
  @GwtCompatible(serializable = true)