InCompletionOrderState<T> state = new InCompletionOrderState<>(copy);
    ImmutableList.Builder<AbstractFuture<T>> delegatesBuilder =
        ImmutableList.builderWithExpectedSize(copy.length);
    for (int i = 0; i < copy.length; i++) {
      delegatesBuilder.add(new InCompletionOrderFuture<T>(state));
    }

    ImmutableList<AbstractFuture<T>> delegates = delegatesBuilder.build();

      int maxSize = maxSize();
      if (maxSize == 0) {
        return ImmutableSet.of();
      }
      ImmutableSet.Builder<@NonNull E> builder = ImmutableSet.builderWithExpectedSize(maxSize);
      for (E element : this) {
        builder.add(checkNotNull(element));
      }
      return builder.build();
    }

    /**

      int maxSize = maxSize();
      if (maxSize == 0) {
        return ImmutableSet.of();
      }
      ImmutableSet.Builder<@NonNull E> builder = ImmutableSet.builderWithExpectedSize(maxSize);
      for (E element : this) {
        builder.add(checkNotNull(element));
      }
      return builder.build();
    }

    /**

    if (values instanceof List || values instanceof ImmutableCollection) {
      return uniqueIndex(
          values.iterator(),
          keyFunction,
          ImmutableMap.builderWithExpectedSize(((Collection<?>) values).size()));
    }
    return uniqueIndex(values.iterator(), keyFunction);
  }

  /**

    if (values instanceof List || values instanceof ImmutableCollection) {
      return uniqueIndex(
          values.iterator(),
          keyFunction,
          ImmutableMap.builderWithExpectedSize(((Collection<?>) values).size()));
    }
    return uniqueIndex(values.iterator(), keyFunction);
  }

  /**