* objects per entry.  Instead we use an open-addressed hash table.  This design is basically
   * equivalent to RegularImmutableSet, save that instead of having a hash table containing the
   * elements directly and null for empty positions, we store indices of the keys in the hash table,
   * and ABSENT for empty positions.  We then look up the keys in alternatingKeysAndValues.
   *

  private final ImmutableMap<C, ImmutableMap<R, V>> columnMap;

  @SuppressWarnings("Immutable") // We don't modify this after construction.
  private final int[] rowCounts;

  @SuppressWarnings("Immutable") // We don't modify this after construction.
  private final int[] columnCounts;

  @SuppressWarnings("Immutable") // We don't modify this after construction.
  private final @Nullable V[][] values;

   * cannot implement that interface in source code in a way that will compile on both Java 7 and
   * Java 8. If we include the {@code getAnnotatedBounds()} method then its return type means it
   * won't compile on Java 7, while if we don't include the method then the compiler will complain
   * that an abstract method is unimplemented. So instead we use a dynamic proxy to get an

          && knownOrder == KnownOrder.UNKNOWN_ORDER) {
        /*
         * We already know the iterator is an Iterator<E>, and now we know that
         * we called next(), so the returned element must be of type E.
         */
        @SuppressWarnings("unchecked")
        E targetReturnValueFromNext = (E) targetReturnValue;
        /*
         * We have an Iterator<E> and want to cast it to

        /*
         * We wish to test whether or not x <= (sqrtFloor + 0.5)^2 = halfSquare + 0.25. Since both x
         * and halfSquare are integers, this is equivalent to testing whether or not x <=
         * halfSquare. (We have to deal with overflow, though.)
         *
         * If we treat halfSquare as an unsigned long, we know that
         *            sqrtFloor^2 <= x < (sqrtFloor + 1)^2

      assertTrue(afterBurst >= 1000);
    }
  }

  /**
   * This neat test shows that no matter what weights we use in our requests, if we push X amount of
   * permits in a cool state, where X = rate * timeToCoolDown, and we have specified a
   * timeToWarmUp() period, it will cost as the prescribed amount of time. E.g., calling
   * [acquire(5), acquire(1)] takes exactly the same time as [acquire(2), acquire(3), acquire(1)].
   */

     * always call succeedsIn*() to initialize them immediately thereafter.
     *
     * The exception is the *InValueSet fields of multimapHeaderEntry, which are never set. (That
     * works out fine as long as we continue to be careful not to try to delete them or iterate
     * past them.)
     *

          public void run() {
            do {
              // We can't have a GOLDEN_NOT_PRESENT_KEY because false positives are
              // possible! It's false negatives that can't happen.
              assertThat(bloomFilter.mightContain(GOLDEN_PRESENT_KEY)).isTrue();

              int key = getNonGoldenRandomKey();
              // We can't check that the key is mightContain() == false before the

      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() {