Method freeze

lib/ModuleGraph.js:964–967

* Processes the provided cache stage. * @param {string=} cacheStage a persistent stage name for caching

(cacheStage)

	 * @param {string=} cacheStage a persistent stage name for caching
	 */
	freeze(cacheStage) {
		this._cache = new WeakTupleMap();
		this._cacheStage = cacheStage;
	}

	unfreeze() {
		this._cache = undefined;