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

In previous versions of Python, you could have used threads or [Gevent](https://www.gevent.org/). But the code is way more complex to understand, debug, and think about.

In previous versions of NodeJS / Browser JavaScript, you would have used "callbacks". Which leads to "callback hell".

        // Default constructor
    }

    /**
     * Adds an ingester to the factory.
     * The ingester is inserted into the collection and the array is re-sorted by priority.
     * This method is thread-safe.
     *
     * @param ingester the ingester to add
     */
    public synchronized void add(final Ingester ingester) {
        if (logger.isDebugEnabled()) {

            try {
                // Wait before retry (except first attempt)
                if (attempt > 0) {
                    long delay = retryDelay * (1L << attempt); // Exponential backoff
                    Thread.sleep(delay);
                    log.debug("Reconnection attempt {} for {}", attempt + 1, info.getPath());
                }

                // Perform the actual reconnection

 *
 * <p>As of Guava 23.0, this class is thread-safe and lock-free. It internally uses atomics and
 * compare-and-swap to ensure correctness when multiple threads are used to access it.
 *
 * @param <T> the type of instances that the {@code BloomFilter} accepts
 * @author Dimitris Andreou
 * @author Kevin Bourrillion
 * @since 11.0 (thread-safe since 23.0)
 */
@Beta

/**
 * The abstract helper for configuration.
 *
 * This class provides a basic framework for managing configurations that can be reloaded.
 * It includes functionality for updating configurations in a separate thread and controlling the reloading interval.
 */
public abstract class AbstractConfigHelper {

    /**
     * Default constructor.
     */
    public AbstractConfigHelper() {
        // Default constructor
    }

                    throwValidationError(messages -> messages.addErrorsCrudCouldNotFindCrudTable(GLOBAL, id), this::asListHtml);
                    return null;
                });
    }

    /**
     * Print a thread dump.
     * @param form The edit form.
     * @return The HTML response.
     */
    @Execute
    @Secured({ ROLE })
    public HtmlResponse threaddump(final EditForm form) {

    public void finalizeReferent() {
      finalizeReferentCalled = true;
    }
  }

  /**
   * Keeps a weak reference to the underlying reference queue. When this reference is cleared, we
   * know that the background thread has stopped and released its strong reference.
   */
  private WeakReference<ReferenceQueue<Object>> queueReference;

  @Test
  public void testThatFinalizerStops() {
    weaklyReferenceQueue();

    CountDownLatch doneSignal = new CountDownLatch(1);
    Thread thread =
        new Thread(
            () -> {
              try {
                cache.get(key, loader);
              } catch (UncheckedExecutionException | ExecutionException e) {
                doneSignal.countDown();
              }
            });
    thread.start();

    boolean done = doneSignal.await(1, SECONDS);

    CountDownLatch doneSignal = new CountDownLatch(1);
    Thread thread =
        new Thread(
            () -> {
              try {
                cache.get(key, loader);
              } catch (UncheckedExecutionException | ExecutionException e) {
                doneSignal.countDown();
              }
            });
    thread.start();

    boolean done = doneSignal.await(1, SECONDS);

        } catch (final UnsupportedEncodingException e) {
            throw new CurlException("Invalid encoding: " + encoding, e);
        }
    }

    /**
     * Sets the thread pool for executing the request.
     *
     * @param threadPool the thread pool
     * @return this CurlRequest instance
     */
    public CurlRequest threadPool(final ForkJoinPool threadPool) {
        this.threadPool = threadPool;