public static KeyId ofString(String keyId) {
        Objects.requireNonNull(keyId);
        return new KeyId(toUtf8Bytes(keyId));
    }
Construct a KeyId containing the UTF-8 byte representation of the given string.

@param keyId a string whose UTF-8 byte representation will be the key ID. May be
             zero-length but not null.
@return a new KeyId instance
security-utils/src/main/java/com/yahoo/security/KeyId.java