assertEquals("", matcher.removeFrom(""));
    assertEquals("", matcher.replaceFrom("", 'z'));
    assertEquals("", matcher.replaceFrom("", "ZZ"));
    assertEquals("", matcher.trimFrom(""));
    assertEquals(0, matcher.countIn(""));
  }

  @J2ktIncompatible
  @GwtIncompatible // NullPointerTester
  private static void doTestNull(CharMatcher matcher) throws Exception {
    NullPointerTester tester = new NullPointerTester();

    teststring = newTestString(new Random(1), bitSet, percentMatching);
  }

  @Benchmark
  public int countIn(int reps) {
    int result = 0;
    CharMatcher matcher = this.matcher;
    String teststring = this.teststring;
    for (int i = 0; i < reps; i++) {
      result += matcher.countIn(teststring);
    }
    return result;
  }

  @Benchmark
  public int collapseFrom(int reps) {
    int result = 0;

    assertEquals("", matcher.removeFrom(""));
    assertEquals("", matcher.replaceFrom("", 'z'));
    assertEquals("", matcher.replaceFrom("", "ZZ"));
    assertEquals("", matcher.trimFrom(""));
    assertEquals(0, matcher.countIn(""));
  }

  @J2ktIncompatible
  @GwtIncompatible // NullPointerTester
  private static void doTestNull(CharMatcher matcher) throws Exception {
    NullPointerTester tester = new NullPointerTester();

   *
   * <p>Counts 2 per supplementary character, such as for {@link #whitespace}().{@link #negate}().
   */
  public int countIn(CharSequence sequence) {
    int count = 0;
    for (int i = 0; i < sequence.length(); i++) {
      if (matches(sequence.charAt(i))) {
        count++;
      }
    }
    return count;
  }

  /**

    return multiset(ImmutableMap.of(value1, count1, value2, count2));
  }

  private static <T> ImmutableMultiset<T> multiset(Map<T, Integer> counts) {
    ImmutableMultiset.Builder<T> builder = ImmutableMultiset.builder();
    for (Entry<T, Integer> entry : counts.entrySet()) {
      builder.addCopies(entry.getKey(), entry.getValue());
    }
    return builder.build();
  }

    return multiset(ImmutableMap.of(value1, count1, value2, count2));
  }

  private static <T> ImmutableMultiset<T> multiset(Map<T, Integer> counts) {
    ImmutableMultiset.Builder<T> builder = ImmutableMultiset.builder();
    for (Entry<T, Integer> entry : counts.entrySet()) {
      builder.addCopies(entry.getKey(), entry.getValue());
    }
    return builder.build();
  }

    for (int i = 0; i < SIZE; i++) {
      aa.set(i, (double) COUNTDOWN);
    }
    Counter c1 = new Counter(aa);
    Counter c2 = new Counter(aa);
    Thread t1 = newStartedThread(c1);
    Thread t2 = newStartedThread(c2);
    awaitTermination(t1);
    awaitTermination(t2);
    assertEquals(SIZE * COUNTDOWN, c1.counts + c2.counts);
  }

  /** a deserialized serialized array holds same values */

     * Stores a crawling configuration in the session-based storage with a unique identifier.
     * The generated session count ID combines the session ID with an incrementing counter.
     *
     * @param sessionId the session identifier
     * @param crawlingConfig the crawling configuration to store
     * @return the unique session count ID that can be used to retrieve the stored configuration
     */

            count = new AtomicInteger(1);
        }

        /**
         * Increments the reference count for this statistics object.
         *
         * @return the new reference count after incrementing
         */
        public int increment() {
            return count.incrementAndGet();
        }

        /**
         * Decrements the reference count for this statistics object.
         *

  @Override
  public int setCount(E element, int count) {
    checkIsE(element);
    checkNonnegative(count, "count");
    int index = element.ordinal();
    int oldCount = counts[index];
    counts[index] = count;
    size += count - oldCount;
    if (oldCount == 0 && count > 0) {
      distinctElements++;
    } else if (oldCount > 0 && count == 0) {
      distinctElements--;
    }
    return oldCount;