code: func SignDetached(version Version, plaintext []byte, signer SigningSecretKey) ([]byte, error) {
  	buf, err := signToStream(version, plaintext, signer, NewSignDetachedStream)
  	if err != nil {
  		return nil, err
  	}
  	return buf.Bytes(), nil
  }
docs: // SignDetached returns a detached signature of plaintext from
  // signer.