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();
        }
      }
    } finally {

          public Boolean get() {
            // Check that this method is called exactly once, by the first
            // thread to synchronize.
            long t0 = System.nanoTime();
            while (waitingThreads() != numThreads - 1) {
              if (System.nanoTime() - t0 > timeout) {
                thrown.set(
                    new TimeoutException(
                        "timed out waiting for other threads to block"

          public Boolean get() {
            // Check that this method is called exactly once, by the first
            // thread to synchronize.
            long t0 = System.nanoTime();
            while (waitingThreads() != numThreads - 1) {
              if (System.nanoTime() - t0 > timeout) {
                thrown.set(
                    new TimeoutException(
                        "timed out waiting for other threads to block"

            return true;
          } else if (nanos <= 0) {
            return false;
          } else {
            long now = System.nanoTime();
            TimeUnit.NANOSECONDS.timedWait(lock, nanos);
            nanos -= System.nanoTime() - now; // subtract the actual time we waited
          }
        }
      }
    }

    /**

        .build();

    final long startNanos = System.nanoTime();
    final Call call = client.newCall(request);

    // Schedule a job to cancel the call in 1 second.
    executor.schedule(() -> {
      System.out.printf("%.2f Canceling call.%n", (System.nanoTime() - startNanos) / 1e9f);
      call.cancel();
      System.out.printf("%.2f Canceled call.%n", (System.nanoTime() - startNanos) / 1e9f);
    }, 1, TimeUnit.SECONDS);

    if (profileTests) runTestProfiled();
    else super.runTest();
  }

  protected void runTestProfiled() throws Throwable {
    long t0 = System.nanoTime();
    try {
      super.runTest();
    } finally {
      long elapsedMillis = (System.nanoTime() - t0) / (1000L * 1000L);
      if (elapsedMillis >= profileThreshold)
        System.out.printf("%n%s: %d%n", toString(), elapsedMillis);
    }
  }

   * - System.nanoTime() is expensive enough that we want to call it the minimum required number of
   *   times, typically once before invoking a blocking method. This often requires keeping track of
   *   the first time in a method that nanoTime() has been invoked, for which the special value 0L
   *   is reserved to mean "uninitialized". If timeout is non-positive, then nanoTime need never be
   *   called.

  }

  private static final class PrintingEventListener extends EventListener {
    long callStartNanos;

    private void printEvent(String name) {
      long nowNanos = System.nanoTime();
      if (name.equals("callStart")) {
        callStartNanos = nowNanos;
      }
      long elapsedNanos = nowNanos - callStartNanos;
      System.out.printf("%.3f %s%n", elapsedNanos / 1000000000d, name);
    }

      // the extra memory consumption and indirection are more
      // expensive than the extra volatile reads.
      long nanos = expirationNanos;
      long now = System.nanoTime();
      if (nanos == 0 || now - nanos >= 0) {
        synchronized (this) {
          if (nanos == expirationNanos) { // recheck for lost race
            T t = delegate.get();
            value = t;

 * (by default) uses {@link System#nanoTime}, it is unaffected by these changes.
 *
 * <p>Use this class instead of direct calls to {@link System#nanoTime} for two reasons:
 *
 * <ul>
 *   <li>The raw {@code long} values returned by {@code nanoTime} are meaningless and unsafe to use
 *       in any other way than how {@code Stopwatch} uses them.