byte[] server = hex("0102030405060708");
        byte[] clientChallenge = hex("0102030405060708");
        long nanos1601 = 0x1122334455667788L;
        byte[] avPairs = hex("A1A2A3A4");

        // Manually build the expected NTLMv2 blob (same as production code)
        int avPairsLength = avPairs.length;
        byte[] blob = new byte[28 + avPairsLength + 4];
        Encdec.enc_uint32le(0x00000101, blob, 0); // Header

That documentation will show up in the Swagger UI at `/docs` in your API, and it will let external developers know how to build the *external API*.

This example doesn't implement the callback itself (that could be just a line of code), only the documentation part.

/// tip

The actual callback is just an HTTP request.

In the next chapter about [FastAPI in Containers - Docker](docker.md){.internal-link target=_blank} I'll explain some strategies you could use to handle the other **deployment concepts**.

I'll show you how to **build your own image from scratch** to run a single Uvicorn process. It is a simple process and is probably what you would want to do when using a distributed container management system like **Kubernetes**.

## Recap { #recap }

        .protocols(ONLY_HTTP1)
        .build()
    val request =
      originalRequest
        .newBuilder()
        .header("Upgrade", "websocket")
        .header("Connection", "Upgrade")
        .header("Sec-WebSocket-Key", key)
        .header("Sec-WebSocket-Version", "13")
        .header("Sec-WebSocket-Extensions", "permessage-deflate")
        .build()

      replacementMap.put(c, replacement);
      return this;
    }

    /** Returns a new escaper based on the current state of the builder. */
    public Escaper build() {
      return new ArrayBasedCharEscaper(replacementMap, safeMin, safeMax) {
        private final char @Nullable [] replacementChars =
            unsafeReplacement != null ? unsafeReplacement.toCharArray() : null;

 *
 * @author Chris Povirk
 * @author Kevin Bourrillion
 */
@GwtCompatible
@Ignore("test runners must not instantiate and run this directly, only via suites we build")
// @Ignore affects the Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.
@SuppressWarnings("JUnit4ClassUsedInJUnit3")
public class MapPutTester<K, V> extends AbstractMapTester<K, V> {

    protected LoadingCache<String, List<Pattern>> createFilterCache(final String type) {
        return CacheBuilder.newBuilder()//
                .expireAfterWrite(filterCacheExpireAfterWrite, TimeUnit.SECONDS)//
                .build(new CacheLoader<String, List<Pattern>>() {

                    /**
                     * Loads filter patterns for the given session ID.
                     *
                     * @param key The session ID.

                        + DEFAULT_TEST_TOKEN + "\"}\n")
                .when()
                .post(getEsUrl() + "/_bulk");
        given().contentType("application/json").when().post(getEsUrl() + "/_refresh");
        logger.info("Created Token: {}", DEFAULT_TEST_TOKEN);
        return DEFAULT_TEST_TOKEN;
    }

 * @param <V> the value type of the map to be tested.
 * @author George van den Driessche
 */
@GwtCompatible
@Ignore("test runners must not instantiate and run this directly, only via suites we build")
// @Ignore affects the Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.
@SuppressWarnings("JUnit4ClassUsedInJUnit3")
@NullMarked

            this.preauthSalt = salt;

            if (config.isEncryptionEnabled()) {
                // Build cipher list based on AES-256 support
                List<Integer> ciphers = new ArrayList<>();

                // Prefer GCM over CCM for better performance
                if (config.isAES256Enabled()) {