if (future.listenersField == expect) {
          future.listenersField = update;
          return true;
        }
        return false;
      }
    }

    @Override
    @Nullable Listener gasListeners(AbstractFutureState<?> future, Listener update) {
      synchronized (future) {
        Listener old = future.listenersField;
        if (old != update) {
          future.listenersField = update;

    /**
     * Contains the most recently submitted {@code Future}, which may be cancelled or updated,
     * always under a lock.
     */
    private static final class SupplantableFuture implements Cancellable {
      private final ReentrantLock lock;

      @GuardedBy("lock")
      private Future<@Nullable Void> currentFuture;

      SupplantableFuture(ReentrantLock lock, Future<@Nullable Void> currentFuture) {
        this.lock = lock;

import static com.google.common.cache.CacheBuilder.UNSET_INT;
import static com.google.common.util.concurrent.Futures.immediateFailedFuture;
import static com.google.common.util.concurrent.Futures.immediateFuture;
import static com.google.common.util.concurrent.Futures.transform;
import static com.google.common.util.concurrent.MoreExecutors.directExecutor;

import static com.google.common.truth.Truth.assertThat;
import static com.google.common.truth.Truth.assertWithMessage;
import static com.google.common.util.concurrent.Futures.immediateFailedFuture;
import static com.google.common.util.concurrent.Futures.immediateFuture;
import static java.util.Arrays.asList;
import static java.util.concurrent.TimeUnit.MILLISECONDS;
import static java.util.concurrent.TimeUnit.SECONDS;

import static com.google.common.truth.Truth.assertThat;
import static com.google.common.truth.Truth.assertWithMessage;
import static com.google.common.util.concurrent.Futures.immediateFailedFuture;
import static com.google.common.util.concurrent.Futures.immediateFuture;
import static java.util.Arrays.asList;
import static java.util.concurrent.TimeUnit.MILLISECONDS;
import static java.util.concurrent.TimeUnit.SECONDS;

# History, Design and Future { #history-design-and-future }

Some time ago, <a href="https://github.com/fastapi/fastapi/issues/3#issuecomment-454956920" class="external-link" target="_blank">a **FastAPI** user asked</a>:

> What’s the history of this project? It seems to have come from nowhere to awesome in a few weeks [...]

Here's a little bit of that history.

## Alternatives { #alternatives }

Cela signifie que **FastAPI** a été spécifiquement testé avec les éditeurs utilisés par 80% des développeurs Python. Et comme la plupart des autres éditeurs ont tendance à fonctionner de façon similaire, tous ses avantages devraient fonctionner pour pratiquement tous les éditeurs.

# История, проектирование и будущее { #history-design-and-future }

Однажды, <a href="https://github.com/fastapi/fastapi/issues/3#issuecomment-454956920" class="external-link" target="_blank">один из пользователей **FastAPI** задал вопрос</a>:

> Какова история этого проекта? Создаётся впечатление, что он явился из ниоткуда и завоевал мир за несколько недель [...]

Что ж, вот небольшая часть истории проекта.

## Альтернативы { #alternatives }

# Geschichte, Design und Zukunft { #history-design-and-future }

Vor einiger Zeit fragte <a href="https://github.com/fastapi/fastapi/issues/3#issuecomment-454956920" class="external-link" target="_blank">ein **FastAPI**-Benutzer</a>:

> Was ist die Geschichte dieses Projekts? Es scheint aus dem Nichts in ein paar Wochen zu etwas Großartigem geworden zu sein [...]

Hier ist ein wenig über diese Geschichte.

## Alternativen { #alternatives }

# Historia, Diseño y Futuro { #history-design-and-future }

Hace algún tiempo, <a href="https://github.com/fastapi/fastapi/issues/3#issuecomment-454956920" class="external-link" target="_blank">un usuario de **FastAPI** preguntó</a>:

> ¿Cuál es la historia de este proyecto? Parece haber surgido de la nada y ser increíble en pocas semanas [...]

Aquí hay un poquito de esa historia.

## Alternativas { #alternatives }