* Creates and returns a new instance of {@link ConcurrentSkipListMap}.
     *
     * @param <K> the key type of {@link ConcurrentSkipListMap}
     * @param <V> the value type of {@link ConcurrentSkipListMap}
     * @return a new instance of {@link ConcurrentSkipListMap}
     * @see ConcurrentSkipListMap#ConcurrentSkipListMap()
     */
    public static <K, V> ConcurrentSkipListMap<K, V> newConcurrentSkipListMap() {

import java.util.List;
import java.util.Random;
import java.util.concurrent.Callable;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.ConcurrentSkipListMap;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Future;
import java.util.concurrent.atomic.AtomicInteger;
import junit.framework.TestCase;

import java.util.Random;
import java.util.Set;
import java.util.SortedMap;
import java.util.TreeSet;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.ConcurrentSkipListMap;
import org.jspecify.annotations.NullUnmarked;

/**
 * Helper classes for various benchmarks.
 *
 * @author Christopher Swenson
 */
@NullUnmarked
final class BenchmarkHelpers {