* its runtime check.
   *
   * <p>An example use case for this method is in implementing an {@code Iterator<T>} whose {@code
   * next} field is lazily initialized. The type of that field would be {@code @Nullable T}, and the
   * code would be responsible for populating a "real" {@code T} (which might still be the value
   * {@code null}!) before returning it to callers. Depending on how the code is structured, a

    assertEquals(
        "Shouldn't catch any more events when unregistered.", expectedEvents, catcher1.getEvents());
    assertEquals("Two correct events should be delivered.", expectedEvents, catcher2.getEvents());

    assertThrows(IllegalArgumentException.class, () -> bus.unregister(catcher1));

    bus.unregister(catcher2);
    bus.post(EVENT);
    assertEquals(

    assertEquals(
        "Shouldn't catch any more events when unregistered.", expectedEvents, catcher1.getEvents());
    assertEquals("Two correct events should be delivered.", expectedEvents, catcher2.getEvents());

    assertThrows(IllegalArgumentException.class, () -> bus.unregister(catcher1));

    bus.unregister(catcher2);
    bus.post(EVENT);
    assertEquals(

  /*
   * If n <= millerRabinBases[i][0], then testing n against bases millerRabinBases[i][1..] suffices
   * to prove its primality. Values from miller-rabin.appspot.com.
   *
   * NOTE: We could get slightly better bases that would be treated as unsigned, but benchmarks
   * showed negligible performance improvements.
   */
  private static final long[][] millerRabinBaseSets = {
    {291830, 126401071349994536L},

      int result = BigIntegerMath.log2(x, HALF_UP);
      BigInteger x2 = x.pow(2);
      // x^2 < 2^(2 * result + 1), or else we would have rounded up
      assertTrue(ZERO.setBit(2 * result + 1).compareTo(x2) > 0);
      // x^2 >= 2^(2 * result - 1), or else we would have rounded down
      assertTrue(result == 0 || ZERO.setBit(2 * result - 1).compareTo(x2) <= 0);
    }
  }

  public void testLog2HalfDown() {

      int result = BigIntegerMath.log2(x, HALF_UP);
      BigInteger x2 = x.pow(2);
      // x^2 < 2^(2 * result + 1), or else we would have rounded up
      assertTrue(ZERO.setBit(2 * result + 1).compareTo(x2) > 0);
      // x^2 >= 2^(2 * result - 1), or else we would have rounded down
      assertTrue(result == 0 || ZERO.setBit(2 * result - 1).compareTo(x2) <= 0);
    }
  }

  public void testLog2HalfDown() {

    /*
     * Safe because all we do is remove values for the key, not add them. (If we wanted to make sure
     * to call getCopy and removeAllNodes only with a true K, then we could check containsKey first.
     * But that check wouldn't eliminate the warnings.)
     */
    @SuppressWarnings({"unchecked", "nullness"})
    K castKey = (K) key;
    List<V> oldValues = getCopy(castKey);
    removeAllNodes(castKey);

    for (int i = 0; i < 8; i++) {
      limiter.acquire(); // // #4
    }
    stopwatch.sleepMillis(500); // #5: to repay for the last acquire
    stopwatch.sleepMillis(2000); // #6: didn't get cold! It would take another 2 seconds to go cold
    for (int i = 0; i < 8; i++) {
      limiter.acquire(); // #7
    }
    assertEvents(
        "R0.00, R1.38, R1.13, R0.88, R0.63, R0.50, R0.50, R0.50", // #1

    ImmutableNetwork.Builder<String, Integer> immutableNetworkBuilder =
        networkBuilder.<String, Integer>immutable();

    // Update NetworkBuilder, but this shouldn't impact immutableNetworkBuilder
    networkBuilder.allowsSelfLoops(false).nodeOrder(ElementOrder.<String>unordered());

    ImmutableNetwork<String, Integer> emptyNetwork = immutableNetworkBuilder.build();

    ImmutableValueGraph.Builder<String, Integer> immutableValueGraphBuilder =
        graphBuilder.<String, Integer>immutable();

    // Update ValueGraphBuilder, but this shouldn't impact immutableValueGraphBuilder
    graphBuilder.allowsSelfLoops(false).nodeOrder(ElementOrder.<String>unordered());

    ImmutableValueGraph<String, Integer> emptyGraph = immutableValueGraphBuilder.build();