func NewShake256() ShakeHash {
	if h := newShake256Asm(); h != nil {
		return h
	}
	return &state{rate: 136, dsbyte: 0x1f}
}
NewShake256 creates a new SHAKE256 variable-output-length ShakeHash.
Its generic security strength is 256 bits against all attacks if
at least 64 bytes of its output are used.
package sha3
import (
	"io"
)
type ShakeHash interface {
	io.Writer
	io.Reader
	Clone() ShakeHash
	Reset()
}
func (d *state) Clone() ShakeHash {
	return d.clone()
}
func NewShake128() ShakeHash {
	if h := newShake128Asm(); h != nil {
		return h
	}
	return &state{rate: 168, dsbyte: 0x1f}
}