public ImmutableSortedMap<K, V> buildOrThrow() {
      switch (size) {
        case 0:
          return emptyMap(comparator);
        case 1:
          // We're careful to put only K and V instances in.
          // requireNonNull is safe because the first `size` elements have been filled in.
          ImmutableSortedMap<K, V> result =

	// Only interested in flushing the size_t not mtime/atime
	if err = Fdatasync(w); err != nil {
		w.Close()
		return err
	}

	// Dealing with error returns from close() - 'man 2 close'
	//
	// A careful programmer will check the return value of close(), since it is quite possible that
	// errors on a previous write(2) operation are reported only on the final close() that releases
	// the open file descriptor.
	//

      int adjust = size() - 1;
      for (int i = 0; i < axes.size(); i++) {
        adjust *= 31;
        adjust = ~~adjust;
        // in GWT, we have to deal with integer overflow carefully
      }
      int hash = 1;
      for (Set<E> axis : axes) {
        hash = 31 * hash + (size() / axis.size() * axis.hashCode());

        hash = ~~hash;
      }
      hash += adjust;