* ReferenceQueue}.
 *
 * @author Bob Lee
 * @since 2.0
 */
@J2ktIncompatible
@GwtIncompatible
public abstract class FinalizableSoftReference<T> extends SoftReference<T>
    implements FinalizableReference {
  /**
   * Constructs a new finalizable soft reference.
   *
   * @param referent to softly reference
   * @param queue that should finalize the referent
   */

import java.io.Serializable;

/** An ordering that uses the natural order of the string representation of the values. */
@GwtCompatible
final class UsingToStringOrdering extends Ordering<Object> implements Serializable {
  static final UsingToStringOrdering INSTANCE = new UsingToStringOrdering();

  @Override
  public int compare(Object left, Object right) {
    return left.toString().compareTo(right.toString());
  }

 */
@GwtCompatible
@J2ktIncompatible
@SuppressWarnings("EnumOrdinal") // This is one of the low-level utilities where it's suitable.
public final class EnumMultiset<E extends Enum<E>> extends AbstractMultiset<E>
    implements Serializable {
  /** Creates an empty {@code EnumMultiset}. */
  public static <E extends Enum<E>> EnumMultiset<E> create(Class<E> type) {
    return new EnumMultiset<>(type);
  }

  /**

import org.jspecify.annotations.NullMarked;

/**
 * String creation for testing arbitrary collections.
 *
 * @author Jared Levy
 */
@GwtCompatible
@NullMarked
public abstract class TestStringCollectionGenerator implements TestCollectionGenerator<String> {
  @Override
  public SampleElements<String> samples() {
    return new Strings();
  }

  @Override
  public Collection<String> create(Object... elements) {

import org.jspecify.annotations.NullMarked;

/**
 * Create queue of strings for tests.
 *
 * @author Jared Levy
 */
@GwtCompatible
@NullMarked
public abstract class TestStringQueueGenerator implements TestQueueGenerator<String> {
  @Override
  public SampleElements<String> samples() {
    return new Strings();
  }

  @Override
  public Queue<String> create(Object... elements) {

import org.jspecify.annotations.Nullable;

/**
 * A mutable value of type {@code int}, for multisets to use in tracking counts of values.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
final class Count implements Serializable {
  private int value;

  Count(int value) {
    this.value = value;
  }

  public int get() {
    return value;
  }

  public void add(int delta) {
    value += delta;
  }

import org.jspecify.annotations.Nullable;

/**
 * Simple base class to verify that we handle generics correctly.
 *
 * @author Kevin Bourrillion
 */
@GwtCompatible
public class BaseComparable implements Comparable<BaseComparable>, Serializable {
  private final String s;

  public BaseComparable(String s) {
    this.s = s;
  }

  @Override
  public int hashCode() { // delegate to 's'

 * Optional features of classes derived from {@code Set}.
 *
 * @author George van den Driessche
 */
@SuppressWarnings("rawtypes") // maybe avoidable if we rework the whole package?
@GwtCompatible
public enum SetFeature implements Feature<Set> {
  GENERAL_PURPOSE(CollectionFeature.GENERAL_PURPOSE);

  private final Set<Feature<? super Set>> implied;

  SetFeature(Feature<? super Set>... implied) {
    this.implied = copyToSet(implied);
  }

 *
 * @author Louis Wasserman
 */
@GwtCompatible
abstract class TransformedIterator<F extends @Nullable Object, T extends @Nullable Object>
    implements Iterator<T> {
  final Iterator<? extends F> backingIterator;

  TransformedIterator(Iterator<? extends F> backingIterator) {
    this.backingIterator = checkNotNull(backingIterator);
  }

  @ParametricNullness

import static java.util.Objects.requireNonNull;

/**
 * Base class for requests.
 *
 * @since 4.0.0
 */
@Experimental
abstract class BaseRequest<S extends ProtoSession> implements Request<S> {

    private final S session;
    private final RequestTrace trace;

    protected BaseRequest(@Nonnull S session) {
        this(session, null);
    }