Weakref 目录 WeakMap (class) WeakMap::count WeakMap::current WeakMap::key WeakMap::next WeakMap::offsetExists WeakMap::offsetGet WeakMap::offsetSet WeakMap::offsetUnset WeakMap::rewind WeakMap::valid WeakMap::__construct WeakRef (class) Weakref::acquire Weakref::get Weakref::release Weakref::valid Weakref::__construct