protected abstract void sleepMicrosUninterruptibly(long micros);

    public static SleepingStopwatch createFromSystemTimer() {
      return new SleepingStopwatch() {
        final Stopwatch stopwatch = Stopwatch.createStarted();

        @Override
        protected long readMicros() {
          return stopwatch.elapsed(MICROSECONDS);
        }

        @Override

    protected abstract void sleepMicrosUninterruptibly(long micros);

    public static SleepingStopwatch createFromSystemTimer() {
      return new SleepingStopwatch() {
        final Stopwatch stopwatch = Stopwatch.createStarted();

        @Override
        protected long readMicros() {
          return stopwatch.elapsed(MICROSECONDS);
        }

        @Override

  @CheckForNull
  Map<K, V> loadAll(Set<? extends K> keys, CacheLoader<? super K, V> loader)
      throws ExecutionException {
    checkNotNull(loader);
    checkNotNull(keys);
    Stopwatch stopwatch = Stopwatch.createStarted();
    Map<K, V> result;
    boolean success = false;
    try {
      @SuppressWarnings("unchecked") // safe since all keys extend K
      Map<K, V> map = (Map<K, V>) loader.loadAll(keys);