@VisibleForTesting transient int expectedValuesPerKey;

  /**
   * Creates a new, empty {@code ArrayListMultimap} with the default initial capacities.
   *
   * <p>You may also consider the equivalent {@code
   * MultimapBuilder.hashKeys().arrayListValues().build()}, which provides more control over the
   * underlying data structure.
   */

    final AtomicBoolean shutdown;

    Interruptenator(Thread interruptee) {
      this(interruptee, new AtomicBoolean(false));
    }

    @SuppressWarnings("ThreadPriorityCheck") // TODO: b/175898629 - Consider onSpinWait.
    Interruptenator(Thread interruptee, AtomicBoolean shutdown) {
      super(
          new Runnable() {
            @Override
            public void run() {
              while (!shutdown.get()) {

    final AtomicBoolean shutdown;

    Interruptenator(Thread interruptee) {
      this(interruptee, new AtomicBoolean(false));
    }

    @SuppressWarnings("ThreadPriorityCheck") // TODO: b/175898629 - Consider onSpinWait.
    Interruptenator(Thread interruptee, AtomicBoolean shutdown) {
      super(
          new Runnable() {
            @Override
            public void run() {
              while (!shutdown.get()) {

### When Adding Features

1. Read existing code first (use symbol overview tools)
2. Follow existing patterns
3. Add tests
4. Handle resources properly (try-with-resources)
5. Consider thread safety
6. Update JavaDoc

### When Fixing Bugs

1. Write failing test first
2. Understand root cause
3. Minimal changes
4. Verify no regressions

### When Refactoring

 * <li>For high-security applications, consider using AES with GCM mode via {@link #setAlgorithm(String)} and {@link #setTransformation(String)}</li>
 * <li>Ensure keys are securely generated and stored</li>
 * <li>For production systems with stringent security requirements, consider using authenticated encryption modes</li>
 * </ul>
 * <p>
 * <strong>Usage Example:</strong>
 * </p>

 * </p>
 * <pre>
 * Map&lt;K, V&gt; syncMap = Collections.synchronizedMap(new LruHashMap&lt;&gt;(100));
 * </pre>
 * <p>
 * Alternatively, for high-concurrency scenarios, consider implementing a custom
 * LRU cache using {@link java.util.concurrent.ConcurrentHashMap} with an eviction strategy.
 * </p>
 *
 * @author koichik
 * @param <K> the key type
 * @param <V> the value type
 */

    while (from.read(buf) != -1) {
      Java8Compatibility.flip(buf);
      to.append(buf);
      total += buf.remaining();
      Java8Compatibility.clear(buf);
    }
    return total;
  }

  // TODO(lukes): consider allowing callers to pass in a buffer to use, some callers would be able
  // to reuse buffers, others would be able to size them more appropriately than the constant
  // defaults

  /**

   * <p>To get the only element in a single-element {@code Iterable}, consider using {@link
   * #getOnlyElement(Iterable)} or {@link #getOnlyElement(Iterable, Object)} instead.
   *
   * <p><b>{@code Stream} equivalent:</b> {@code stream.findFirst().orElse(defaultValue)}
   *
   * <p><b>Java 21+ users:</b> if {code iterable} is a {@code SequencedCollection} (e.g., any list),

      }
    }

    // Test _all_ allowed characters (including surrogate values).
    for (char ch = 0x20; ch <= 0xFFFD; ch++) {
      // There are a small number of cases to consider, so just do it manually.
      if (ch == '&') {
        assertEscaping(xmlEscaper, "&amp;", ch);
      } else if (ch == '<') {
        assertEscaping(xmlEscaper, "&lt;", ch);
      } else if (ch == '>') {

      return CollectSpliterators.indexed(size(), SPLITERATOR_CHARACTERISTICS, this::get);
    }

    @Override
    public void forEach(Consumer<? super E> consumer) {
      checkNotNull(consumer);
      int n = size();
      for (int i = 0; i < n; i++) {
        consumer.accept(get(i));
      }
    }

    @Override
    int copyIntoArray(@Nullable Object[] dst, int offset) {