Function IsCurrentExecutor

cpp/src/arrow/util/future_test.cc:1088–1088

    int GetCapacity() override { return pool_->GetCapacity(); }

    bool IsCurrentExecutor() override { return pool_->IsCurrentExecutor(); }

    Status SpawnReal(internal::TaskHints hints, internal::FnOnce<void()> task,
                     StopToken stop_token, StopCallback&& stop_callback) override {