}

  void checkEmpty(BlockingQueue<?> q) {
    try {
      assertTrue(q.isEmpty());
      assertEquals(0, q.size());
      assertThat(q.peek()).isNull();
      assertThat(q.poll()).isNull();
      assertThat(q.poll(0, MILLISECONDS)).isNull();
      assertEquals("[]", q.toString());
      assertThat(q.toArray()).isEmpty();
      assertFalse(q.iterator().hasNext());
      try {
        q.element();

      // If even the first one wasn't there, clean up so that the next test doesn't see an element.
      producerThread.cancel(true);
      producer.doneProducing.await();
      if (drained == 0) {
        q.poll(); // not necessarily there if producer was interrupted
      }
    }
  }

  public void testDrainOverflow() throws InterruptedException {

      |ujLQkfk/fuJt/T5pVQ1vUEqxfcMw0zYgszQ5C2MiIl7M6JkTRKU01q9hVFCR83wX
      |zIdrLQIDAQABAkEA7dEA9o/5k77y68ZhRv9z7QEwucBcKzQ3rsSCbWMpYqg924F9
      |L8Z76kzSedSO2PN8mg6y/OLL+qBuTeUK/yiowQIhAP0cknFMbqeNX6uvj/S+V7in
      |bIhQkhcSdJjRw8fxMnJpAiEA9WTp9wzJpn+9etZo0jJ8wkM0+LTMNELo47Ctz7l1
      |kiUCIQCi34vslD5wWyzBEcwUtZdFH5dbcF1Rs3KMFA9jzfWkYQIgHtiWiFV1K5a3

            .removalListener(listener)
            .ticker(ticker)
            .build();
    cache.put(1, 1);
    ticker.advance(10, MINUTES);
    cache.invalidateAll();

    assertThat(listener.poll().getCause()).isEqualTo(RemovalCause.EXPIRED);
  }

  private void runRemovalScheduler(
      LoadingCache<String, Integer> cache,
      CountingRemovalListener<String, Integer> removalListener,

	SUBV	R4, R5			// a5901100
	ADD	R4, R5			// a5101000
	ADDW	R4, R5			// a5101000
	ADDV	R4, R5			// a5901000
	AND	R4, R5			// a5901400
	NEGW	R4, R5			// 05101100
	NEGV	R4, R5			// 05901100
	SLL	R4, R5			// a5101700
	SLL	R4, R5, R6		// a6101700
	SRL	R4, R5			// a5901700
	SRL	R4, R5, R6	 	// a6901700
	SRA	R4, R5			// a5101800
	SRA	R4, R5, R6	 	// a6101800
	ROTR	R4, R5			// a5101b00
	ROTR	R4, R5, R6		// a6101b00

      while (true) {
        Future<T> f = futureQueue.poll();
        if (f == null) {
          if (ntasks > 0) {
            --ntasks;
            futures.add(submitAndAddQueueListener(executorService, it.next(), futureQueue));
            ++active;
          } else if (active == 0) {
            break;
          } else if (timed) {
            f = futureQueue.poll(timeoutNanos, TimeUnit.NANOSECONDS);

* Traefik (that can also handle certificate renewals)
* Caddy (that can also handle certificate renewals)
* Nginx
* HAProxy

## Let's Encrypt { #lets-encrypt }

Before Let's Encrypt, these **HTTPS certificates** were sold by trusted third parties.

The process to acquire one of these certificates used to be cumbersome, require quite some paperwork and the certificates were quite expensive.

    void execute() {
      synchronized (runnables) {
        if (executed) {
          return;
        }
        executed = true;
      }

      while (!runnables.isEmpty()) {
        runnables.poll().execute();
      }
    }

    private static class RunnableExecutorPair {
      final Runnable runnable;
      final Executor executor;

      RunnableExecutorPair(Runnable runnable, Executor executor) {

      "take plan 1",
      "plan 0 cancel",
      "plan 0 TCP connect canceled",
    )
  }

  private fun assertEvents(vararg expected: String) {
    val actual = generateSequence { routePlanner.events.poll() }.toList()
    assertThat(actual).containsExactly(*expected)
  }

  private val Int.ms: Long
    get() = this * 1_000_000L

     * not in {@link #nextElements}, this method throws an {@link UnknownElementException}.
     *
     * <p>This method is used when testing iterators without a known ordering. We poll the target
     * iterator's next element and pass it to the reference iterator through this method so it can
     * return the same element. This enables the assertion to pass and the reference iterator to