Function sync

src/core/impl/comp_node_api.cpp:27–33

}

void sync(mgbComputeNode_t cn) {
    if (!is_finalize()) {
        auto* s = reinterpret_cast<mgb::CompNode*>(cn);
        if (s->valid())
            s->sync();
    }
}

mgbComputeNode_t load_cuda_cn(int device_id, int stream) {
    std::string loc = ssprintf("gpu%i:%i", device_id, stream);