Method clear_all

src/core/impl/graph/var_node_mem_mgr.cpp:82–89

#if MGB_THREAD_SAFE
size_t StaticDeviceMemoryManager::clear_all() {
    size_t ret = 0;
    for (auto&& i : m_storage) {
        update_max(ret, i.second.use_count());
    }
    m_storage.clear();
    return ret;
}

std::shared_ptr<StaticDeviceMemoryManager> StaticDeviceMemoryManager::
        make_default_impl() {