presto-raptor-legacy/src/main/java/io/prestosql/plugin/raptor/legacy/util/PrioritizedFifoExecutor.java/PrioritizedFifoExecutor/submit
class PrioritizedFifoExecutor:    public ListenableFuture<?> submit(T task)
    {
        FifoRunnableTask<T> fifoTask = new FifoRunnableTask<>(task, sequenceNumber.incrementAndGet(), taskComparator);
        queue.add(fifoTask);
        executorService.submit(triggerTask);
        return fifoTask;
    }