/*
   * This class is used to serialize all ImmutableSortedSet instances,
   * regardless of implementation type. It captures their "logical contents"
   * only. This is necessary to ensure that the existence of a particular
   * implementation type is an implementation detail.
   */
  @J2ktIncompatible // serialization
  private static class SerializedForm<E> implements Serializable {

  /*
   * This class is used to serialize all ImmutableSortedSet instances,
   * regardless of implementation type. It captures their "logical contents"
   * only. This is necessary to ensure that the existence of a particular
   * implementation type is an implementation detail.
   */
  @J2ktIncompatible // serialization
  private static class SerializedForm<E> implements Serializable {

   * contents to empty. By contrast, the non-GWT constructor with the same signature uses the
   * comparator only as a comparator. It does NOT assume empty contents. (It requires an
   * implementation of iterator() to define its contents, and methods like contains() are
   * implemented in terms of that method (though they will likely be overridden by subclasses for