android/guava/src/com/google/common/hash/AbstractByteHasher.java
protected void update(byte[] b, int off, int len) {
    for (int i = off; i < off + len; i++) {
      update(b[i]);
    }
  }
protected void update(byte[] b, int off, int len) {
    for (int i = off; i < off + len; i++) {
      update(b[i]);
    }
  }
Updates this hasher with {@code len} bytes starting at {@code off} in the given buffer.