*/
  @SuppressWarnings("unchecked")
  public static <T extends @Nullable Object> Collector<T, ?, T> onlyElement() {
    return (Collector) ONLY_ELEMENT;
  }

  /**
   * This atrocity is here to let us report several of the elements in the stream if there were more
   * than one, not just two.
   */
  @SuppressWarnings("EmptyList") // ImmutableList doesn't support nullable element types

          shift += 24;
          len += 3;
        } else {
          int codePoint = Character.codePointAt(input, i);
          if (codePoint == c) {
            // not a valid code point; let the JDK handle invalid Unicode
            return hashBytes(input.toString().getBytes(charset));
          }
          i++;
          buffer |= codePointToFourUtf8Bytes(codePoint) << shift;

import junit.framework.TestCase;
import junit.framework.TestSuite;
import org.jspecify.annotations.NullUnmarked;

/**
 * Collection tests on wrappers from {@link Multisets}.
 *
 * @author Jared Levy
 */
@GwtIncompatible // suite // TODO(cpovirk): set up collect/gwt/suites version
@NullUnmarked
@AndroidIncompatible // test-suite builders
public class MultisetsCollectionTest extends TestCase {

import java.util.Map;
import java.util.Set;
import junit.framework.TestSuite;

/**
 * Creates, based on your criteria, a JUnit test suite that exhaustively tests a {@code Multiset}
 * implementation.
 *
 * @author Jared Levy
 * @author Louis Wasserman
 */
@GwtIncompatible
public class MultisetTestSuiteBuilder<E>
    extends AbstractCollectionTestSuiteBuilder<MultisetTestSuiteBuilder<E>, E> {

                  CollectionFeature.RESTRICTS_ELEMENTS,
                  ListFeature.SUPPORTS_SET)
              .createTestSuite());
    }
    return suite;
  }

  // Test generators.  To let the GWT test suite generator access them, they need to be
  // public named classes with a public default constructor.

  public static final class ShortsAsListGenerator extends TestShortListGenerator {
    @Override

                  CollectionFeature.RESTRICTS_ELEMENTS,
                  ListFeature.SUPPORTS_SET)
              .createTestSuite());
    }
    return suite;
  }

  // Test generators.  To let the GWT test suite generator access them, they need to be
  // public named classes with a public default constructor.

  public static final class LongsAsListGenerator extends TestLongListGenerator {
    @Override

                  CollectionFeature.RESTRICTS_ELEMENTS,
                  ListFeature.SUPPORTS_SET)
              .createTestSuite());
    }
    return suite;
  }

  // Test generators.  To let the GWT test suite generator access them, they need to be
  // public named classes with a public default constructor.

  public static final class ShortsAsListGenerator extends TestShortListGenerator {
    @Override

import java.util.Collections;
import java.util.List;
import junit.framework.TestCase;
import org.jspecify.annotations.NullMarked;

/**
 * Tests for {@link Multisets}.
 *
 * @author Mike Bostock
 * @author Jared Levy
 * @author Louis Wasserman
 */
@GwtCompatible
@NullMarked
public class MultisetsTest extends TestCase {

  /* See MultisetsImmutableEntryTest for immutableEntry() tests. */

      return FluentIterable.from(inputs)
          .<FluentFuture<?>>transform(future -> future.future)
          .toList();
    }
  }

  /**
   * A generic {@link Combiner} that lets you use a lambda or method reference to combine two {@link
   * ClosingFuture}s. Use {@link #whenAllSucceed(ClosingFuture, ClosingFuture)} to start this
   * combination.
   *

 *
 * <p>This class assists the implementation of collection classes. Do not use this class to
 * serialize collections that are defined elsewhere.
 *
 * @author Jared Levy
 */
@GwtIncompatible
@J2ktIncompatible
final class Serialization {
  private Serialization() {}

  /**
   * Reads a count corresponding to a serialized map, multiset, or multimap. It returns the size of