presto-blackhole/src/main/java/io/prestosql/plugin/blackhole/BlackHolePageSink.java/BlackHolePageSink/scheduleAppend
class BlackHolePageSink:    private CompletableFuture<Collection<Slice>> scheduleAppend()
    {
        if (pageProcessingDelayMillis > 0) {
            return toCompletableFuture(executorService.schedule(() -> ImmutableList.of(), pageProcessingDelayMillis, MILLISECONDS));
        }
        return NON_BLOCKED;
    }