CollectorTester<T, A, R> of(
          Collector<T, A, R> collector, BiPredicate<? super R, ? super R> equivalence) {
    return new CollectorTester<>(collector, equivalence);
  }

  private final Collector<T, A, R> collector;
  private final BiPredicate<? super R, ? super R> equivalence;

  private CollectorTester(
      Collector<T, A, R> collector, BiPredicate<? super R, ? super R> equivalence) {

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
import java.util.function.BiPredicate;
import java.util.stream.Collector;
import junit.framework.Test;
import junit.framework.TestCase;
import junit.framework.TestSuite;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

import com.google.errorprone.annotations.ForOverride;
import com.google.errorprone.annotations.InlineMe;
import java.io.Serializable;
import java.util.Objects;
import java.util.function.BiPredicate;
import org.jspecify.annotations.NonNull;
import org.jspecify.annotations.Nullable;

/**
 * A strategy for determining whether two instances are considered equivalent, and for computing

import java.util.Arrays;
import java.util.Collection;
import java.util.Comparator;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
import java.util.function.BiPredicate;
import junit.framework.Test;
import junit.framework.TestCase;
import junit.framework.TestSuite;
import org.jspecify.annotations.NullUnmarked;

/**
 * Tests for {@link ImmutableSortedMultiset}.
 *

import java.util.Comparator;
import java.util.Iterator;
import java.util.NoSuchElementException;
import java.util.Set;
import java.util.SortedSet;
import java.util.TreeSet;
import java.util.function.BiPredicate;
import java.util.stream.Collector;
import junit.framework.Test;
import junit.framework.TestSuite;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**

import com.google.common.testing.SerializableTester;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.Map.Entry;
import java.util.Spliterator;
import java.util.function.BiPredicate;
import java.util.stream.Collector;
import junit.framework.Test;
import junit.framework.TestCase;
import junit.framework.TestSuite;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

 * {@linkplain #identity() identity equivalence} and the {@linkplain #equals "equals" equivalence}.
 *
 * <p><b>For users targeting Android API level 24 or higher:</b> This class will eventually
 * implement {@code BiPredicate<T, T>} (as it does in the main Guava artifact), but we currently
 * target a lower API level. In the meantime, if you have support for method references you can use

import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicReferenceArray;
import java.util.concurrent.locks.ReentrantLock;
import java.util.function.BiFunction;
import java.util.function.BiPredicate;
import java.util.function.Function;
import java.util.function.Predicate;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.jspecify.annotations.NullUnmarked;