data.put("message", phaseMessage);
                        if (keywords != null) {
                            data.put("keywords", keywords);
                        }
                        sendSseEvent(writer, "phase", data);
                        if (logger.isDebugEnabled()) {
                            logger.debug("SSE phase start event sent. phase={}, message={}, keywords={}", phase, phaseMessage, keywords);

    @Test
    public void test_sendSseEvent_basic() {
        final StringWriter stringWriter = new StringWriter();
        final PrintWriter writer = new PrintWriter(stringWriter);

        chatApiManager.sendSseEvent(writer, "test", Map.of("key", "value"));

        final String output = stringWriter.toString();
        assertTrue(output.contains("event: test"));
        assertTrue(output.contains("data:"));