CrawlingParameterUtil.setUrlQueueService(urlQueueService);
        CrawlingParameterUtil.setDataService(dataService);
        try {
            while (crawlerContext.getStatus() != CrawlerStatus.DONE && isContinue(threadCheckCount)) {
                final UrlQueue<?> urlQueue = urlQueueService.poll(crawlerContext.sessionId);
                if (isValid(urlQueue)) {
                    ResponseData responseData = null;

    public static void load( InputStream in ) throws IOException {
        if( in != null ) {
            prp.load( in );
        }
        try {
            prp.putAll( (java.util.Map)System.getProperties().clone() );
        } catch( SecurityException se ) {
            if( log.level > 1 )
                log.println( "SecurityException: jcifs.smb1 will ignore System properties" );
        }
    }

}

/** Returns an immutable list containing [elements]. */
@SafeVarargs
internal fun <T> immutableListOf(vararg elements: T): List<T> {
  return Collections.unmodifiableList(listOf(*elements.clone()))
}

/** Closes this, ignoring any checked exceptions. */
internal fun Socket.closeQuietly() {
  try {
    close()
  } catch (e: AssertionError) {
    throw e
  } catch (rethrown: RuntimeException) {

  override fun timeout(): Timeout = timeout

  @SuppressWarnings("CloneDoesntCallSuperClone") // We are a final type & this saves clearing state.
  override fun clone(): Call = RealCall(client, originalRequest, forWebSocket)

  override fun request(): Request = originalRequest

  /**
   * Immediately closes the socket connection if it's currently held. Use this to interrupt an

          // entryArray) in the Kotlin translation.
          Entry<K, V>[] originalEntries = entries;
          entries = originalEntries.clone();
        }
      }
      entries[entryIndex] = effectiveEntry;
    }
    if (duplicates != null) {
      // Explicit type parameters needed here to avoid a problem with nullness inference.

pkg runtime/debug, type BuildSetting struct
pkg runtime/debug, type BuildSetting struct, Key string
pkg runtime/debug, type BuildSetting struct, Value string
pkg strings, func Clone(string) string
pkg strings, func Cut(string, string) (string, string, bool)
pkg strings, func Title //deprecated
pkg sync, method (*Mutex) TryLock() bool
pkg sync, method (*RWMutex) TryLock() bool

				}
				break
			}
			if want := testOutput[done : done+len(line)]; !bytes.Equal(want, line) {
				t.Errorf("Bad line at stride %d: want: %x got: %x", stride, want, line)
			}
			done += len(line)
		}
		if done != len(testOutput) {
			t.Errorf("ReadLine didn't return everything: got: %d, want: %d (stride: %d)", done, len(testOutput), stride)
		}
	}
}

func TestReadLine(t *testing.T) {

	ch := make(chan struct {
		err       error
		scopeName string
	}, len(scopes))
	var wg sync.WaitGroup
	for _, scope := range scopes {
		wg.Add(1)
		go func(si *ScopeInfo) {
			defer wg.Done()
			err := c.PutScope(si)
			ch <- struct {
				err       error
				scopeName string
			}{err: err, scopeName: si.Name}
		}(scope)
	}
	wg.Wait()
	close(ch)
	for result := range ch {

Then your API will (let's imagine):

* Send the invoice to some customer of the external developer.
* Collect the money.
* Send a notification back to the API user (the external developer).
    * This will be done by sending a POST request (from *your API*) to some *external API* provided by that external developer (this is the "callback").

## The normal **FastAPI** app

	r.input = make(chan *queueItem, runtime.GOMAXPROCS(0))
	r.readerWg.Add(1)

	// Start splitter
	go func() {
		defer close(r.input)
		defer close(r.queue)
		defer r.readerWg.Done()
		for {
			q := queueItem{
				input: next,
				dst:   make(chan [][]string, 1),
				err:   nextErr,
			}
			select {
			case <-r.close:
				return
			case r.queue <- &q:
			}