public byte[] toBytes() {
        String authzid = authorizationId.isEmpty() ? "" : "a=" + authorizationId;
        String extensions = extensionsMessage();
        if (!extensions.isEmpty())
            extensions = SEPARATOR + extensions;

        String message = String.format("n,%s,%sauth=Bearer %s%s%s%s", authzid,
                SEPARATOR, tokenValue, extensions, SEPARATOR, SEPARATOR);

        return message.getBytes(StandardCharsets.UTF_8);
    }
@Test
    public void testBuildClientResponseToBytes() throws Exception {
        String expectedMessage = "n,,\u0001auth=Bearer 123.345.567\u0001nineteen=42\u0001\u0001";

        Map<String, String> extensions = new HashMap<>();
        extensions.put("nineteen", "42");
        OAuthBearerClientInitialResponse response = new OAuthBearerClientInitialResponse("123.345.567", new SaslExtensions(extensions));

        String message = new String(response.toBytes(), StandardCharsets.UTF_8);

        assertEquals(expectedMessage, message);
    }