Method Cancel

library/cpp/par/par_exec.h:93–101

            return MasterGuid;
        }
        void Cancel() {
            if (AtomicCas(&CurrentState, -1, 0)) {
                if (CompleteNotify.Get()) {
                    CompleteNotify->MRCommandComplete(true, nullptr);
                    CompleteNotify = nullptr;
                } else
                    Y_ASSERT(0 && "Notify ptr is lost");
            }
        }
        bool NeedResult() {
            if (AtomicGet(CurrentState) != 0)
                return false;