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();

    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();
  }

     * 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;

      void doIt(ImmutableDoubleArray.Builder builder, AtomicInteger counter) {
        builder.add(counter.getAndIncrement());
      }
    },
    ADD_ARRAY {
      @Override
      void doIt(ImmutableDoubleArray.Builder builder, AtomicInteger counter) {
        double[] array = new double[random.nextInt(10)];
        for (int i = 0; i < array.length; i++) {
          array[i] = counter.getAndIncrement();
        }

     * Gets the total number of records in the search result set.
     *
     * @return the total record count
     */
    public long getAllRecordCount() {
        return allRecordCount;
    }

    /**
     * Gets the relation type for the total record count.
     *
     * @return the relation type (e.g., "eq" for exact count, "gte" for greater than or equal)
     */
    public String getAllRecordCountRelation() {