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) {

    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) {

      characteristics &= splitr.characteristics();
      estimatedSize = LongMath.saturatedAdd(estimatedSize, splitr.estimateSize());
    }
    return StreamSupport.stream(
            CollectSpliterators.flatMap(
                splitrsBuilder.build().spliterator(),
                splitr -> (Spliterator<T>) splitr,
                characteristics,
                estimatedSize),
            isParallel)

      characteristics &= splitr.characteristics();
      estimatedSize = LongMath.saturatedAdd(estimatedSize, splitr.estimateSize());
    }
    return StreamSupport.stream(
            CollectSpliterators.flatMap(
                splitrsBuilder.build().spliterator(),
                splitr -> (Spliterator<T>) splitr,
                characteristics,
                estimatedSize),
            isParallel)

   * 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)