@SuppressWarnings("NullAway")
  static @Nullable <V> V getIfReady(@Nullable CompletableFuture<V> future) {
    return isReady(future) ? future.join() : null;
  }
@Test(dataProvider = "successful")
  public void getIfReady_success(CompletableFuture<Integer> future) {
    assertThat(Async.getIfReady(future)).isEqualTo(1);
  }