code: func NewShake128() ShakeHash {
  	if h := newShake128Asm(); h != nil {
  		return h
  	}
  	return &state{rate: 168, dsbyte: 0x1f}
  }
docs: // NewShake128 creates a new SHAKE128 variable-output-length ShakeHash.
  // Its generic security strength is 128 bits against all attacks if at
  // least 32 bytes of its output are used.