docs: private static ThreadFactory getThreadFactory(final String nameFormat) {
          final ThreadFactory defaultThreadFactory = Executors.privilegedThreadFactory();
          return new ThreadFactory() {
              final AtomicLong count = (nameFormat != null) ? new AtomicLong(0) : null;
  
              @Override
              public Thread newThread(Runnable runnable) {
                  Thread thread = defaultThreadFactory.newThread(runnable);
                  if (nameFormat != null) {
                      thread.setName(String.format(nameFormat, count.getAndIncrement()));
                  }
                  return thread;
              }
          };
      }