Method checkin

async_simple/executors/SimpleExecutor.h:72–82

    }

    bool checkin(Func func, Context ctx, ScheduleOptions opts) override {
        int64_t id = reinterpret_cast<int64_t>(ctx);
        auto prompt =
            _pool.getCurrentId() == (id & (~kContextMask)) && opts.prompt;
        if (prompt) {
            func();
            return true;
        }
        return _pool.scheduleById(std::move(func), id & (~kContextMask)) ==
               util::ThreadPool::ERROR_NONE;
    }

    IOExecutor* getIOExecutor() override { return &_ioExecutor; }