В прежних версиях NodeJS/браузерного JavaScript вы бы использовали «callbacks» (обратные вызовы), что приводит к «callback hell» (ад обратных вызовов).

## Сопрограммы { #coroutines }

     * not in {@link #nextElements}, this method throws an {@link UnknownElementException}.
     *
     * <p>This method is used when testing iterators without a known ordering. We poll the target
     * iterator's next element and pass it to the reference iterator through this method so it can
     * return the same element. This enables the assertion to pass and the reference iterator to

automatically\n  &:empty {\n    display: none;\n  }\n}\n\n// Quick fix for badges in buttons\n.btn .badge {\n  position: relative;\n  top: -1px;\n}\n\n// Pill badges\n//\n// Make them extra rounded with a modifier to replace v3's badges.\n\n.badge-pill {\n  padding-right: $badge-pill-padding-x;\n  padding-left: $badge-pill-padding-x;\n  @include border-radius($badge-pill-border-radius);\n}\n\n// Colors\n//\n// Contextual variations (linked badges get darker on :hover).\n\n@each $color, $value in $theme-colors...

   * Acknowledge: A communication control character transmitted by a receiver as an affirmative
   * response to a sender.
   *
   * @since 8.0
   */
  public static final byte ACK = 6;

  /**
   * Bell ('\a'): A character for use when there is a need to call for human attention. It may
   * control alarm or attention devices.
   *
   * @since 8.0
   */
  public static final byte BEL = 7;

  /**

xt-align:center;width:2em;line-height:inherit}.fa-border{border:.08em solid #eee;border-radius:.1em;padding:.2em .25em .15em}.fa-pull-left{float:left}.fa-pull-right{float:right}.fa.fa-pull-left,.fab.fa-pull-left,.fal.fa-pull-left,.far.fa-pull-left,.fas.fa-pull-left{margin-right:.3em}.fa.fa-pull-right,.fab.fa-pull-right,.fal.fa-pull-right,.far.fa-pull-right,.fas.fa-pull-right{margin-left:.3em}.fa-spin{-webkit-animation:fa-spin 2s linear infinite;animation:fa-spin 2s linear infinite}.fa-pulse{-web...

falling down a very deep well.

  Either the well was very deep, or she fell very slowly, for she
had plenty of time as she went down to look about her and to
wonder what was going to happen next.  First, she tried to look
down and make out what she was coming to, but it was too dark to
see anything; then she looked at the sides of the well, and
noticed that they were filled with cupboards and book-shelves;

            requestQueue.offer(new CrawlRequest(url, 0));
            while (!requestQueue.isEmpty() && (maxAccessCount < 0 || counter < maxAccessCount)) {
                final CrawlRequest crawlRequest = requestQueue.poll();
                if ((maxDepth != -1 && crawlRequest.getDepth() > maxDepth) || processedUrls.contains(crawlRequest.getUrl())) {
                    if (logger.isDebugEnabled()) {

    /*
     * TODO(lowasser): consider checking for ImmutableAsList here
     * TODO(lowasser): consider checking for Multiset here
     */
    // Don't refer to ImmutableSortedSet by name so it won't pull in all that code
    if (elements instanceof ImmutableSet && !(elements instanceof SortedSet)) {
      @SuppressWarnings("unchecked") // all supported methods are covariant
      ImmutableSet<E> set = (ImmutableSet<E>) elements;

## In a hurry? { #in-a-hurry }

<abbr title="too long; didn't read"><strong>TL;DR:</strong></abbr>

If you are using third party libraries that tell you to call them with `await`, like:

```Python
results = await some_library()
```

Then, declare your *path operation functions* with `async def` like:

```Python hl_lines="2"
@app.get('/')

Dans les versions précédentes de JavaScript côté navigateur / NodeJS, vous auriez utilisé des « callbacks ». Menant potentiellement à ce que l'on appelle le « callback hell ».

## Coroutines { #coroutines }