} else if (i % DIRECT_EXECUTIONS_PER_THREAD == DIRECT_EXECUTIONS_PER_THREAD - 1) {
          // When at max depth, record stack trace depth
          lengthChecks.add(
              serializer.submit(
                  new Callable<Integer>() {
                    @Override
                    public Integer call() {
                      holder.count++;
                      return Thread.currentThread().getStackTrace().length;

        } else if (i % DIRECT_EXECUTIONS_PER_THREAD == DIRECT_EXECUTIONS_PER_THREAD - 1) {
          // When at max depth, record stack trace depth
          lengthChecks.add(
              serializer.submit(
                  new Callable<Integer>() {
                    @Override
                    public Integer call() {
                      holder.count++;
                      return Thread.currentThread().getStackTrace().length;

   * accommodate as many threads as will ever concurrently modify the table. Using a significantly
   * higher value than you need can waste space and time, and a significantly lower value can lead
   * to thread contention. But overestimates and underestimates within an order of magnitude do not
   * usually have much noticeable impact. A value of one permits only one thread to modify the map

                // Explicitly yield to increase the probability of a pathological scheduling.
                Thread.yield();
                return new Schedule(0, SECONDS);
              }
            };
          }
        };
    service.useBarriers = false;
    service.startAsync().awaitRunning();
    Thread.sleep(50);
    service.useBarriers = true;
    service.firstBarrier.await();

 * {@link Map} specified in the {@link Table} interface.
 *
 * <p>Note that this implementation is not synchronized. If multiple threads access this table
 * concurrently and one of the threads modifies the table, it must be synchronized externally.
 *
 * <p>See the Guava User Guide article on <a href=

   */
  internal var interceptorScopedExchange: Exchange? = null
    private set

  // These properties are guarded by [lock]. They are typically only accessed by the thread executing
  // the call, but they may be accessed by other threads for duplex requests.

  /** True if this call still has a request body open. */
  private var requestBodyOpen = false

  /** True if this call still has a response body open. */

                // Explicitly yield to increase the probability of a pathological scheduling.
                Thread.yield();
                return new Schedule(0, SECONDS);
              }
            };
          }
        };
    service.useBarriers = false;
    service.startAsync().awaitRunning();
    Thread.sleep(50);
    service.useBarriers = true;
    service.firstBarrier.await();

 * an {@code ArrayTable} concurrently and one of the threads modifies its value, there is no
 * guarantee that the new value will be fully visible to the other threads. To guarantee that
 * modifications are visible, synchronize access to the table. Unlike other {@code Table}
 * implementations, synchronization is unnecessary between a thread that writes to one cell and a

            // num of threads
            final CrawlerContext crawlerContext = crawler.getCrawlerContext();
            final int numOfThread =
                    webConfig.getNumOfThread() != null ? webConfig.getNumOfThread() : Constants.DEFAULT_NUM_OF_THREAD_FOR_WEB;
            crawlerContext.setNumOfThread(numOfThread);

            // depth

 * acquired, permits need not be released.
 *
 * <p>{@code RateLimiter} is safe for concurrent use: It will restrict the total rate of calls from
 * all threads. Note, however, that it does not guarantee fairness.
 *
 * <p>Rate limiters are often used to restrict the rate at which some physical or logical resource