* @since 19.0 (since 1.0 as constant {@code INVISIBLE})
   */
  @Deprecated
  public static CharMatcher invisible() {
    return Invisible.INSTANCE;
  }

  /**
   * Determines whether a character is single-width (not double-width). When in doubt, this matcher
   * errs on the side of returning {@code false} (that is, it tends to assume a character is
   * double-width).
   *

    doTestSetBits(inRange('n', 'q'));
    doTestSetBits(forPredicate(Predicates.equalTo('c')));
    doTestSetBits(CharMatcher.ascii());
    doTestSetBits(CharMatcher.digit());
    doTestSetBits(CharMatcher.invisible());
    doTestSetBits(CharMatcher.whitespace());
    doTestSetBits(inRange('A', 'Z').and(inRange('F', 'K').negate()));
  }

  @GwtIncompatible // java.util.BitSet
  private void doTestSetBits(CharMatcher matcher) {

    doTestSetBits(inRange('n', 'q'));
    doTestSetBits(forPredicate(Predicates.equalTo('c')));
    doTestSetBits(CharMatcher.ascii());
    doTestSetBits(CharMatcher.digit());
    doTestSetBits(CharMatcher.invisible());
    doTestSetBits(CharMatcher.whitespace());
    doTestSetBits(inRange('A', 'Z').and(inRange('F', 'K').negate()));
  }

  @GwtIncompatible // java.util.BitSet
  private void doTestSetBits(CharMatcher matcher) {

 * is requested entries may be evicted on each cache modification, on occasional cache accesses, or
 * on calls to {@link Cache#cleanUp}. Expired entries may be counted by {@link Cache#size}, but will
 * never be visible to read or write operations.
 *
 * <p>If {@link #weakKeys weakKeys}, {@link #weakValues weakValues}, or {@link #softValues
 * softValues} are requested, it is possible for a key or value present in the cache to be reclaimed

     */
    Waiter(boolean unused) {}

    Waiter() {
      // avoid volatile write, write is made visible by subsequent CAS on waitersField field
      putThread(this, Thread.currentThread());
    }

    // non-volatile write to the next field. Should be made visible by a subsequent CAS on
    // waitersField.
    void setNext(@Nullable Waiter next) {
      putNext(this, next);
    }

 * an {@code ArrayTable} concurrently and one of the threads modifies its value, there is no
 * guarantee that the new value will be fully visible to the other threads. To guarantee that
 * modifications are visible, synchronize access to the table. Unlike other {@code Table}
 * implementations, synchronization is unnecessary between a thread that writes to one cell and a
 * thread that reads from another.
 *

     */
    Waiter(boolean unused) {}

    Waiter() {
      // avoid volatile write, write is made visible by subsequent CAS on waitersField field
      putThread(this, Thread.currentThread());
    }

    // non-volatile write to the next field. Should be made visible by a subsequent CAS on
    // waitersField.
    void setNext(@Nullable Waiter next) {
      putNext(this, next);
    }

  public boolean removeIfZero(K key) {
    return remove(key, 0);
  }

  /**
   * Removes all mappings from this map whose values are zero.
   *
   * <p>This method is not atomic: the map may be visible in intermediate states, where some of the
   * zero values have been removed and others have not.
   */
  public void removeAllZeros() {
    map.values().removeIf(x -> x == 0);
  }

  /**

                  extremeValues.remove(extremeValues.size() - 1);
                  extremeValues.remove(extremeValues.size() - 1);
                }

                // the regular values should be visible after filtering
                List<E> allEntries = new ArrayList<>();
                allEntries.addAll(extremeValues);
                allEntries.addAll(normalValues);
                SortedMultiset<E> multiset =

 * values may be removed from the map on each map modification or on occasional map accesses; such
 * entries may be counted by {@link Map#size}, but will never be visible to read or write
 * operations. A partially-reclaimed entry is never exposed to the user. Any {@link Map.Entry}
 * instance retrieved from the map's {@linkplain Map#entrySet entry set} is a snapshot of that