* other callers have added to it.
       *
       * This read is guaranteed to get us the right value because we only set this once (here).
       *
       * requireNonNull is safe because either our compareAndSet succeeded or it failed because
       * another thread did it for us.
       */
      seenExceptionsLocal = requireNonNull(seenExceptionsField);
    }
    return seenExceptionsLocal;
  }

        executingTaskQueue.thread = null;
      }
    }

    private boolean trySetStarted() {
      return compareAndSet(NOT_RUN, STARTED);
    }

    private boolean trySetCancelled() {
      return compareAndSet(NOT_RUN, CANCELLED);
    }
  }

   * AtomicInteger's atomic operations, with some help from ConcurrentMap's atomic operations on
   * creation and removal (including automatic removal of zeroes). If the modification of an
   * AtomicInteger results in zero, we compareAndSet the value to zero; if that succeeds, we remove
   * the entry from the Map. If another operation sees a zero in the map, it knows that the entry is

   * AtomicInteger's atomic operations, with some help from ConcurrentMap's atomic operations on
   * creation and removal (including automatic removal of zeroes). If the modification of an
   * AtomicInteger results in zero, we compareAndSet the value to zero; if that succeeds, we remove
   * the entry from the Map. If another operation sees a zero in the map, it knows that the entry is

  }

  /**
   * Simulate some of the races that can happen on add. We can't easily simulate the race that
   * happens when an {@link AtomicInteger#compareAndSet} fails, but we can simulate the case where
   * the putIfAbsent returns a non-null value, and the case where the replace() of an observed zero
   * fails.
   */
  public void testAdd_withFailures() {

        if (current == State.OPEN) {
            long timeSinceLastFailure = System.currentTimeMillis() - lastFailureTime.get();
            if (timeSinceLastFailure > timeoutMillis) {
                if (state.compareAndSet(State.OPEN, State.HALF_OPEN)) {
                    stateChangeTime.set(System.currentTimeMillis());
                    halfOpenSuccesses.set(0);

  }

  public void testOrdering() throws Exception {
    AtomicInteger integer = new AtomicInteger();
    for (int i = 0; i < 10; i++) {
      int expectedCount = i;
      list.add(() -> integer.compareAndSet(expectedCount, expectedCount + 1), directExecutor());
    }
    list.execute();
    assertEquals(10, integer.get());
  }

  private static final class MockRunnable implements Runnable {

                if (shouldExecute && anyPredecessorFailed) {
                    // We'll run the step but mark it as SKIPPED instead of SCHEDULED
                    if (step.status.compareAndSet(CREATED, SKIPPED)) {
                        logger.debug(
                                "Running after:* step {} for cleanup but marking it as SKIPPED because a predecessor failed",
                                step);

        }

        ModelObjectProcessor processor = ProcessorHolder.CACHED_PROCESSOR.get();
        if (processor == null) {
            processor = loadProcessor();
            ProcessorHolder.CACHED_PROCESSOR.compareAndSet(null, processor);
            processor = ProcessorHolder.CACHED_PROCESSOR.get();
        }
        return processor.process(object);
    }

    /**
     * Load the first available processor implementation.

    check(executed.compareAndSet(false, true)) { "Already Executed" }

    timeout.enter()
    callStart()
    try {
      client.dispatcher.executed(this)
      return getResponseWithInterceptorChain()
    } finally {
      client.dispatcher.finished(this)
    }
  }

  override fun enqueue(responseCallback: Callback) {
    check(executed.compareAndSet(false, true)) { "Already Executed" }