int numOfByteRead = in.read(buf, 0, buf.length);
    assertEquals(4, numOfByteRead);
    for (int i = 0; i < testBytes.length; i++) {
      assertEquals(testBytes[i], buf[i]);
    }

    verify(hasher).putBytes(testBytes, 0, testBytes.length);
    verify(hashFunction).newHasher();
    verifyNoMoreInteractions(hashFunction, hasher);
  }

  public void testRead_putByteArrayAtPos() throws Exception {

      ensureCapacity(Byte.BYTES);
      buffer.put(b);
      return this;
    }

    @Override
    public Hasher putBytes(byte[] bytes, int off, int len) {
      ensureCapacity(len);
      buffer.put(bytes, off, len);
      return this;
    }

    @Override
    public Hasher putBytes(ByteBuffer bytes) {
      ensureCapacity(bytes.remaining());
      buffer.put(bytes);
      return this;
    }

    ByteBuffer bigEndian = ByteBuffer.wrap(bytes).order(ByteOrder.BIG_ENDIAN);
    assertEquals(
        hashFunction.newHasher().putBytes(littleEndian).hash(),
        hashFunction.newHasher().putBytes(bigEndian).hash());
    assertEquals(ByteOrder.LITTLE_ENDIAN, littleEndian.order());
    assertEquals(ByteOrder.BIG_ENDIAN, bigEndian.order());
  }

      }
    },
    HASH_FUNCTION_VIA_HASHER() {
      @Override
      public byte[] hash(Algorithm algorithm, byte[] input) {
        return algorithm.getHashFunction().newHasher().putBytes(input).hash().asBytes();
      }
    };
    ;

    abstract byte[] hash(Algorithm algorithm, byte[] input);
  }

  private enum Algorithm {
    MD5("MD5", Hashing.md5()),

      }
    },
    HASH_FUNCTION_VIA_HASHER() {
      @Override
      public byte[] hash(Algorithm algorithm, byte[] input) {
        return algorithm.getHashFunction().newHasher().putBytes(input).hash().asBytes();
      }
    };
    ;

    abstract byte[] hash(Algorithm algorithm, byte[] input);
  }

  private enum Algorithm {
    MD5("MD5", Hashing.md5()),

  public Hasher putByte(byte b) {
    update(b);
    return this;
  }

  @Override
  @CanIgnoreReturnValue
  public Hasher putBytes(byte[] bytes) {
    checkNotNull(bytes);
    update(bytes);
    return this;
  }

  @Override
  @CanIgnoreReturnValue
  public Hasher putBytes(byte[] bytes, int off, int len) {
    checkPositionIndexes(off, off + len, bytes.length);
    update(bytes, off, len);
    return this;
  }

  PrimitiveSink putByte(byte b);

  /**
   * Puts an array of bytes into this sink.
   *
   * @param bytes a byte array
   * @return this instance
   */
  @CanIgnoreReturnValue
  PrimitiveSink putBytes(byte[] bytes);

  /**
   * Puts a chunk of an array of bytes into this sink. {@code bytes[off]} is the first byte written,
   * {@code bytes[off + len - 1]} is the last.
   *
   * @param bytes a byte array

   */
  HashCode hashLong(long input);

  /**
   * Shortcut for {@code newHasher().putBytes(input).hash()}. The implementation <i>might</i>
   * perform better than its longhand equivalent, but should not perform worse.
   */
  HashCode hashBytes(byte[] input);

  /**
   * Shortcut for {@code newHasher().putBytes(input, off, len).hash()}. The implementation

   */
  HashCode hashLong(long input);

  /**
   * Shortcut for {@code newHasher().putBytes(input).hash()}. The implementation <i>might</i>
   * perform better than its longhand equivalent, but should not perform worse.
   */
  HashCode hashBytes(byte[] input);

  /**
   * Shortcut for {@code newHasher().putBytes(input, off, len).hash()}. The implementation

  @Override
  public void write(int b) throws IOException {
    hasher.putByte((byte) b);
    out.write(b);
  }

  @Override
  public void write(byte[] bytes, int off, int len) throws IOException {
    hasher.putBytes(bytes, off, len);
    out.write(bytes, off, len);
  }

  /**
   * Returns the {@link HashCode} based on the data written to this stream. The result is