// IsEncrypted reports whether the ETag is encrypted.
func (e ETag) IsEncrypted() bool {
	// An encrypted ETag must be at least 32 bytes long.
	// It contains the encrypted ETag value + an authentication
	// code generated by the AEAD cipher.
	//
	// Here is an incorrect implementation of IsEncrypted:
	//
	//   return len(e) > 16 && !bytes.ContainsRune(e, '-')
	//
	// An encrypted ETag may contain some random bytes - e.g.