Method set_remained

src/bthread/task_group.h:122–125

    // the target to be suspended already.
    typedef void (*RemainedFn)(void*);
    void set_remained(RemainedFn cb, void* arg) {
        _last_context_remained = cb;
        _last_context_remained_arg = arg;
    }
    
    // Suspend caller for at least |timeout_us| microseconds.
    // If |timeout_us| is 0, this function does nothing.