* The listener will run when the {@code Future}'s computation is {@linkplain Future#isDone()
   * complete} or, if the computation is already complete, immediately.
   *
   * <p>There is no guaranteed ordering of execution of listeners, but any listener added through
   * this method is guaranteed to be called once the computation is complete.
   *
   * <p>Exceptions thrown by a listener will be propagated up to the executor. Any exception thrown

        KerberosKey kdcKey = new KerberosKey(null, keyBytes, PacSignature.HMAC_SHA1_96_AES256, 1);
        keys.put(PacSignature.ETYPE_AES256_CTS_HMAC_SHA1_96, kdcKey);

        // Mock Pac construction to bypass complex validation
        try (MockedConstruction<Pac> pacMock = Mockito.mockConstruction(Pac.class, (mock, context) -> {
            // Setup mock behavior
            PacLogonInfo mockLogonInfo = Mockito.mock(PacLogonInfo.class);

        manager.process(request, response, chain);

        assertEquals(201, response.getStatus());
        assertEquals("application/json", response.getHeader("Content-Type"));
        assertEquals("Complex response", response.getWrittenContent());
        assertTrue(chain.wasDoFilterCalled());
    }

    // Test implementation classes

    private static class TestWebApiManager implements WebApiManager {

            // Verify overwrite
            assertEquals(concreteImplementation, cacheMap.get(key));
            assertNotEquals(oldEntry, cacheMap.get(key));
        }
    }

    @Nested
    @DisplayName("Complex Scenarios Tests")
    class ComplexScenariosTests {

        @Test
        @DisplayName("Should handle multiple fixup operations")
        void testMultipleFixupOperations() {

        void shouldHandleResponseMapOperations() {
            assertEquals(0, transport.getResponseMapSize());
            // Response map is accessible through protected field for testing
            // but we avoid complex interactions here for performance
        }
    }

But before that, handling asynchronous code was quite more complex and difficult.

In previous versions of Python, you could have used threads or <a href="https://www.gevent.org/" class="external-link" target="_blank">Gevent</a>. But the code is way more complex to understand, debug, and think about.

        assertEquals(type, exception.getType());
        assertEquals(message, exception.getMessage());
    }

    public void test_exceptionInComplexScenario() {
        // Test exception in a more complex scenario
        InvalidAccessTokenException exception = null;
        String expectedType = "Bearer";
        String expectedMessage = "Token has expired";

        // Simulate a token validation scenario

        assertNotSame(loginException.getMessageCode(), logoutException.getMessageCode());
    }

    public void test_complexMessageCode() {
        // Setup - test with a complex message code that has parameters
        final String errorDetail = "Authentication failed";
        final VaMessenger<FessMessages> complexMessageCode =

        assertNotNull(dataStoreParams.get("camelCaseKey"));

        dataStoreParams.put("snake_case_key", "value2");
        assertNotNull(dataStoreParams.get("snake_case_key"));
    }

    // Test with complex object values
    public void test_complexObjectValues() {
        Map<String, String> complexObject = new HashMap<>();
        complexObject.put("nested", "value");

        assertEquals("custom_field", queryContext.getDefaultField());

        queryContext.setDefaultField(null);
        assertNull(queryContext.getDefaultField());
    }

    // Test complex scenario with multiple operations
    public void test_complexScenario() {
        getMockRequest().setAttribute(Constants.FIELD_LOGS, new HashMap<String, List<String>>());