presto-main/src/main/java/io/prestosql/execution/QueryStateTimer.java/QueryStateTimer/beginPlanning
class QueryStateTimer:    private void beginPlanning(long now)
    {
        beginDispatching(now);
        dispatchingTime.compareAndSet(null, nanosSince(beginDispatchingNanos, now));
        beginPlanningNanos.compareAndSet(null, now);
    }