in src/main/java/com/spotify/futures/FuturesExtra.java [417:427]
public static <Z, A, B> ListenableFuture<Z> asyncTransform2(
ListenableFuture<A> a,
ListenableFuture<B> b,
final AsyncFunction2<Z, ? super A, ? super B> function,
final Executor executor) {
return transform(
Arrays.asList(a, b),
(AsyncFunction<List<Object>, Z>)
results -> function.apply((A) results.get(0), (B) results.get(1)),
executor);
}