try {
      long remainingNanos = unit.toNanos(timeout);
      long end = System.nanoTime() + remainingNanos;

      while (true) {
        try {
          // CountDownLatch treats negative timeouts just like zero.
          return latch.await(remainingNanos, NANOSECONDS);
        } catch (InterruptedException e) {
          interrupted = true;
          remainingNanos = end - System.nanoTime();
        }

      return getDoneValue(localValue);
    }
    // we delay calling nanoTime until we know we will need to either park or spin
    long endNanos = remainingNanos > 0 ? System.nanoTime() + remainingNanos : 0;
    long_wait_loop:
    if (remainingNanos >= SPIN_THRESHOLD_NANOS) {
      Waiter oldHead = waitersField;
      if (oldHead != Waiter.TOMBSTONE) {
        Waiter node = new Waiter();
        do {

            } else {
              long remainingNanos;
              if (startTime == 0L) {
                startTime = initNanoTime(timeoutNanos);
                remainingNanos = timeoutNanos;
              } else {
                remainingNanos = remainingNanos(startTime, timeoutNanos);
              }
              satisfied = awaitNanos(guard, remainingNanos, signalBeforeWaiting);
            }