concatenated.close();
    assertThat(closeCountB.get()).isEqualTo(1);
  }

  public void testConcat_refStream_closeIsPropagated_Stream_concat() {
    // Just to demonstrate behavior of Stream::concat in the standard library
    AtomicInteger closeCountB = new AtomicInteger(0);
    Stream<String> streamB = Stream.of("b").onClose(closeCountB::incrementAndGet);
    Stream<String> concatenated =

/**
 * Provides static methods for working with {@code Collection} instances.
 *
 * <p><b>Java 8+ users:</b> several common uses for this class are now more comprehensively
 * addressed by the new {@link java.util.stream.Stream} library. Read the method documentation below
 * for comparisons. These methods are not being deprecated, but we gently encourage you to migrate
 * to streams.
 *
 * @author Chris Povirk
 * @author Mike Bostock

   * environment that forces Futures.getChecked to its fallback WeakSetValidator. One awful way of
   * doing so would be to derive a separate test library by using remove_from_jar to strip out
   * ClassValueValidator.
   *
   * Fortunately, we get pretty good coverage "by accident": We run all these tests against the
   * *backport*, where ClassValueValidator is not present.

 * implementations in Java use). For the many uses of hash functions beyond data structures,
 * however, {@code Object.hashCode} almost always falls short -- hence this library.
 *
 * @author Kevin Bourrillion
 * @since 11.0
 */
@Immutable
@ElementTypesAreNonnullByDefault
public interface HashFunction {
  /**

 * frac(x) respectively. This is the same definition as used by Excel and by S, it is the Type 7
 * definition in <a
 * href="http://stat.ethz.ch/R-manual/R-devel/library/stats/html/quantile.html">R</a>, and it is
 * described by <a
 * href="http://en.wikipedia.org/wiki/Quantile#Estimating_the_quantiles_of_a_population">

 * in the {@link Iterators} class.
 *
 * <p><b>Java 8+ users:</b> several common uses for this class are now more comprehensively
 * addressed by the new {@link java.util.stream.Stream} library. Read the method documentation below
 * for comparisons. This class is not being deprecated, but we gently encourage you to migrate to
 * streams.
 *

   * environment that forces Futures.getChecked to its fallback WeakSetValidator. One awful way of
   * doing so would be to derive a separate test library by using remove_from_jar to strip out
   * ClassValueValidator.
   *
   * Fortunately, we get pretty good coverage "by accident": We run all these tests against the
   * *backport*, where ClassValueValidator is not present.

/**
 * Provides static methods for working with {@code Collection} instances.
 *
 * <p><b>Java 8+ users:</b> several common uses for this class are now more comprehensively
 * addressed by the new {@link java.util.stream.Stream} library. Read the method documentation below
 * for comparisons. These methods are not being deprecated, but we gently encourage you to migrate
 * to streams.
 *
 * @author Chris Povirk
 * @author Mike Bostock

   * input byte array {@code {0x54, 0x32}} would yield the {@code char} value {@code '\\u5432'}.
   *
   * <p>Arguably, it's preferable to use {@link java.nio.ByteBuffer}; that library exposes much more
   * flexibility at little cost in readability.
   *
   * @throws IllegalArgumentException if {@code bytes} has fewer than 2 elements
   */
  @GwtIncompatible // doesn't work

   * byte array {@code {0x12, 0x13, 0x14, 0x15, 0x33}} would yield the {@code int} value {@code
   * 0x12131415}.
   *
   * <p>Arguably, it's preferable to use {@link java.nio.ByteBuffer}; that library exposes much more
   * flexibility at little cost in readability.
   *
   * @throws IllegalArgumentException if {@code bytes} has fewer than 4 elements
   */
  public static int fromByteArray(byte[] bytes) {