ImmutableList<String> keys = ImmutableList.of("a", "b", "c");
    try {
      List<Future<int[]>> futures = newArrayListWithExpectedSize(nTasks);
      for (int i = 0; i < nTasks; i++) {
        futures.add(pool.submit(new MutateTask(multiset, keys)));
      }

      int[] deltas = new int[3];
      for (Future<int[]> future : futures) {
        int[] taskDeltas = future.get();
        for (int i = 0; i < deltas.length; i++) {

      to that Work or Derivative Works thereof, that is intentionally
      submitted to Licensor for inclusion in the Work by the copyright owner
      or by an individual or Legal Entity authorized to submit on behalf of
      the copyright owner. For the purposes of this definition, "submitted"
      means any form of electronic, verbal, or written communication sent

      final Path file, final Path target, ExecutorService executor) {
    @SuppressWarnings("unused") // https://errorprone.info/bugpattern/FutureReturnValueIgnored
    Future<?> possiblyIgnoredError =
        executor.submit(
            new Runnable() {
              @Override
              public void run() {
                boolean createSymlink = false;
                while (!Thread.interrupted()) {
                  try {