}
      }
      return changed;
    }

    @CheckForNull
    WrappedCollection getAncestor() {
      return ancestor;
    }

    // The following methods are provided for better performance.

    @Override
    public boolean addAll(Collection<? extends V> collection) {
      if (collection.isEmpty()) {
        return false;
      }
      int oldSize = size(); // calls refreshIfEmpty

        }
      }
      return changed;
    }

    @CheckForNull
    WrappedCollection getAncestor() {
      return ancestor;
    }

    // The following methods are provided for better performance.

    @Override
    public boolean addAll(Collection<? extends V> collection) {
      if (collection.isEmpty()) {
        return false;
      }
      int oldSize = size(); // calls refreshIfEmpty