? emptySet(delegate.comparator())
        : new RegularImmutableSortedSet<E>(delegate, isSubset);
  }

  private final transient SortedSet<E> sortedDelegate;

  /**
   * Scary constructor for ContiguousSet. This constructor (in this file, the GWT emulation of
   * ImmutableSortedSet) creates an empty sortedDelegate, which, in a vacuum, sets this object's