*/
@Beta
@ElementTypesAreNonnullByDefault
public interface Hasher extends PrimitiveSink {
  @CanIgnoreReturnValue
  @Override
  Hasher putByte(byte b);

  @CanIgnoreReturnValue
  @Override
  Hasher putBytes(byte[] bytes);

  @CanIgnoreReturnValue
  @Override
  Hasher putBytes(byte[] bytes, int off, int len);

  @CanIgnoreReturnValue
  @Override
  Hasher putBytes(ByteBuffer bytes);

  @CanIgnoreReturnValue

    // https://github.com/aappleby/smhasher/blob/master/src/main.cpp
    HashTestUtils.verifyHashFunction(hf, 32, 0xB0F57EE3);
  }

  public void testParanoid() {
    HashFn hf =
        new HashFn() {
          @Override
          public byte[] hash(byte[] input, int seed) {
            Hasher hasher = murmur3_32(seed).newHasher();
            Funnels.byteArrayFunnel().funnel(input, hasher);
            return hasher.hash().asBytes();

    @CanIgnoreReturnValue
    @Override
    public Hasher putInt(int i) {
      update(4, i);
      return this;
    }

    @CanIgnoreReturnValue
    @Override
    public Hasher putLong(long l) {
      update(4, (int) l);
      update(4, l >>> 32);
      return this;
    }

    @CanIgnoreReturnValue
    @Override
    public Hasher putChar(char c) {
      update(2, c);
      return this;

   */
  public static Escaper nullEscaper() {
    return NULL_ESCAPER;
  }

  // An Escaper that efficiently performs no escaping.
  // Extending CharEscaper (instead of Escaper) makes Escapers.compose() easier.
  private static final Escaper NULL_ESCAPER =
      new CharEscaper() {
        @Override
        public String escape(String string) {
          return checkNotNull(string);
        }

        @Override

      super(master.size() + 3, MODIFIABLE, master, IteratorTester.KnownOrder.KNOWN_ORDER);
      this.master = master;
    }

    @Override
    protected Iterator<T> newTargetIterator() {
      // make copy from master to verify later
      targetList = Lists.newArrayList(master);
      Iterator<T> iterator = targetList.iterator();
      return Iterators.peekingIterator(iterator);
    }

    @Override

  }

  public void testHashIntVsForLoop() {
    int input = 42;
    HashCode expected = Hashing.md5().hashInt(input);

    Hasher hasher = Hashing.md5().newHasher();
    for (int i = 0; i < 32; i += 8) {
      hasher.putByte((byte) (input >> i));
    }
    HashCode actual = hasher.hash();

    assertEquals(expected, actual);
  }

  private static final String EMPTY_STRING = "";

  }

  static HashCode randomHash(HashFunction hashFunction, Random random, int numActions) {
    Hasher hasher = hashFunction.newHasher();
    for (int i = 0; i < numActions; i++) {
      RandomHasherAction.pickAtRandom(random).performAction(random, ImmutableSet.of(hasher));
    }
    return hasher.hash();
  }

  private static void assertShortcutsAreEquivalent(HashFunction hashFunction, int trials) {

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  abstract ImmutableCollection<E> delegateCollection();

  @Override
  public boolean contains(@CheckForNull Object target) {
    // The collection's contains() is at least as fast as ImmutableList's
    // and is often faster.
    return delegateCollection().contains(target);
  }

  @Override
  public int size() {
    return delegateCollection().size();
  }

  @Override
  public boolean isEmpty() {

  abstract ImmutableCollection<E> delegateCollection();

  @Override
  public boolean contains(@CheckForNull Object target) {
    // The collection's contains() is at least as fast as ImmutableList's
    // and is often faster.
    return delegateCollection().contains(target);
  }

  @Override
  public int size() {
    return delegateCollection().size();
  }

  @Override
  public boolean isEmpty() {