public static KeyId ofBytes(byte[] keyIdBytes) {
        Objects.requireNonNull(keyIdBytes);
        return new KeyId(Arrays.copyOf(keyIdBytes, keyIdBytes.length));
    }
@Test
    void too_big_key_id_throws() {
        byte[] tooBigIdBytes = new byte[KeyId.MAX_KEY_ID_UTF8_LENGTH + 1];
        Arrays.fill(tooBigIdBytes, (byte)'A');
        assertThrows(IllegalArgumentException.class, () -> KeyId.ofBytes(tooBigIdBytes));
    }