code: func Digest(in io.Reader) (string, error) {
  	hash := crypto.SHA256.New()
  	io.Copy(hash, in)
  	return hex.EncodeToString(hash.Sum(nil)), nil
  }
docs: // Digest hashes a reader and returns a SHA256 digest.
  //
  // Helm uses SHA256 as its default hash for all non-cryptographic applications.