* 3: "Enforce the singleton property with a private constructor or an enum type". For example:
 *
 * <pre>{@code
 * public enum PersonFunnel implements Funnel<Person> {
 *   INSTANCE;
 *   public void funnel(Person person, PrimitiveSink into) {
 *     into.putUnencodedChars(person.getFirstName())
 *         .putUnencodedChars(person.getLastName())
 *         .putInt(person.getAge());
 *   }
 * }

    @SuppressWarnings({"unchecked", "DoNotMock"})
    Funnel<Object> elementFunnel = mock(Funnel.class);
    PrimitiveSink primitiveSink = mock(PrimitiveSink.class);
    Funnel<Iterable<?>> sequential = Funnels.sequentialFunnel(elementFunnel);
    sequential.funnel(Arrays.asList("foo", "bar", "baz", "quux"), primitiveSink);
    InOrder inOrder = inOrder(elementFunnel);
    inOrder.verify(elementFunnel).funnel("foo", primitiveSink);

    SerializableTester.reserializeAndAssert(bf);
  }

  public void testCustomSerialization() throws Exception {
    Funnel<byte[]> funnel = Funnels.byteArrayFunnel();
    BloomFilter<byte[]> bf = BloomFilter.create(funnel, 100);
    for (int i = 0; i < 100; i++) {
      bf.put(Ints.toByteArray(i));
    }

    ByteArrayOutputStream out = new ByteArrayOutputStream();

  @Override
  Hasher putString(CharSequence charSequence, Charset charset);

  /** A simple convenience for {@code funnel.funnel(object, this)}. */
  @CanIgnoreReturnValue
  <T extends @Nullable Object> Hasher putObject(
      @ParametricNullness T instance, Funnel<? super T> funnel);

  /**
   * Computes a hash code based on the data that have been provided to this hasher. The result is

down a large rabbit-hole under the hedge.

  In another moment down went Alice after it, never once
considering how in the world she was to get out again.

  The rabbit-hole went straight on like a tunnel for some way,
and then dipped suddenly down, so suddenly that Alice had not a
moment to think about stopping herself before she found herself
falling down a very deep well.

        }
        return this;
      }

      @Override
      public <T extends @Nullable Object> Hasher putObject(
          @ParametricNullness T instance, Funnel<? super T> funnel) {
        for (Hasher hasher : hashers) {
          hasher.putObject(instance, funnel);
        }
        return this;
      }

      @Override
      public HashCode hash() {
        return makeHash(hashers);
      }
    };

  /**
   * Shortcut for {@code newHasher().putObject(instance, funnel).hash()}. The implementation
   * <i>might</i> perform better than its longhand equivalent, but should not perform worse.
   *
   * @since 14.0
   */
  <T extends @Nullable Object> HashCode hashObject(
      @ParametricNullness T instance, Funnel<? super T> funnel);

  /**

    HashFn hf =
        new HashFn() {
          @Override
          public byte[] hash(byte[] input, int seed) {
            Hasher hasher = murmur3_128(seed).newHasher();
            Funnels.byteArrayFunnel().funnel(input, hasher);
            return hasher.hash().asBytes();
          }
        };
    // Murmur3F, MurmurHash3 for x64, 128-bit (MurmurHash3_x64_128)
    // From http://code.google.com/p/smhasher/source/browse/trunk/main.cpp

public final class Funnels {
  private Funnels() {}

  /** Returns a funnel that extracts the bytes from a {@code byte} array. */
  public static Funnel<byte[]> byteArrayFunnel() {
    return ByteArrayFunnel.INSTANCE;
  }

  private enum ByteArrayFunnel implements Funnel<byte[]> {
    INSTANCE;

    @Override
    public void funnel(byte[] from, PrimitiveSink into) {
      into.putBytes(from);
    }

    @Override

    @SuppressWarnings({"unchecked", "DoNotMock"})
    Funnel<Object> elementFunnel = mock(Funnel.class);
    PrimitiveSink primitiveSink = mock(PrimitiveSink.class);
    Funnel<Iterable<?>> sequential = Funnels.sequentialFunnel(elementFunnel);
    sequential.funnel(Arrays.asList("foo", "bar", "baz", "quux"), primitiveSink);
    InOrder inOrder = inOrder(elementFunnel);
    inOrder.verify(elementFunnel).funnel("foo", primitiveSink);