return new FilterReader(reader) {
      @Override
      public int read(char[] cbuf, int off, int len) throws IOException {
        // if a buffer isn't being cleared correctly, this method will eventually start being called
        // with a len of 0 forever
        if (len <= 0) {
          fail("read called with a len of " + len);
        }
        // read fewer than the max number of chars to read

    return new FilterReader(reader) {
      @Override
      public int read(char[] cbuf, int off, int len) throws IOException {
        // if a buffer isn't being cleared correctly, this method will eventually start being called
        // with a len of 0 forever
        if (len <= 0) {
          fail("read called with a len of " + len);
        }
        // read fewer than the max number of chars to read

  protected void update(byte[] b) {
    update(b, 0, b.length);
  }

  /** Updates this hasher with {@code len} bytes starting at {@code off} in the given buffer. */
  protected void update(byte[] b, int off, int len) {
    for (int i = off; i < off + len; i++) {
      update(b[i]);
    }
  }

  /** Updates this hasher with bytes from the given buffer. */
  protected void update(ByteBuffer b) {

    super(checkNotNull(in));
    this.random = checkNotNull(random);
  }

  @Override
  public int read(byte[] b, int off, int len) throws IOException {
    return super.read(b, off, random.nextInt(len) + 1);
  }

  }

  /** Returns the number of bytes written. */
  public long getCount() {
    return count;
  }

  @Override
  public void write(byte[] b, int off, int len) throws IOException {
    out.write(b, off, len);
    count += len;
  }

  @Override
  public void write(int b) throws IOException {
    out.write(b);
    count++;
  }

      @Nullable Object[] src, int offset, int len, T[] dst) {
    checkPositionIndexes(offset, offset + len, src.length);
    if (dst.length < len) {
      dst = newArray(dst, len);
    } else if (dst.length > len) {
      @Nullable Object[] unsoundlyCovariantArray = dst;
      unsoundlyCovariantArray[len] = null;
    }
    arraycopy(src, offset, dst, 0, len);
    return dst;
  }

  /**

    return putBytes(bytes, 0, bytes.length);
  }

  @Override
  @CanIgnoreReturnValue
  public Hasher putBytes(byte[] bytes, int off, int len) {
    Preconditions.checkPositionIndexes(off, off + len, bytes.length);
    for (int i = 0; i < len; i++) {
      putByte(bytes[off + i]);
    }
    return this;
  }

  @Override
  @CanIgnoreReturnValue
  public Hasher putBytes(ByteBuffer b) {

    super(checkNotNull(in));
    this.random = checkNotNull(random);
  }

  @Override
  public int read(byte[] b, int off, int len) throws IOException {
    return super.read(b, off, random.nextInt(len) + 1);
  }

    int len = sequence.length();
    for (int i = 0; i < len; i++) {
      char c = sequence.charAt(i);
      if (matches(c)) {
        if (c == replacement && (i == len - 1 || !matches(sequence.charAt(i + 1)))) {
          // a no-op replacement
          i++;
        } else {
          StringBuilder builder = new StringBuilder(len).append(sequence, 0, i).append(replacement);

        flush();
      }

      @Override
      public void write(char[] cbuf, int off, int len) throws IOException {
        super.write(cbuf, off, len);
        flush();
      }

      @Override
      public void write(String str, int off, int len) throws IOException {
        super.write(str, off, len);
        flush();
      }
    };
  }