getContextTsh(path, callback) {
		const cache = this._contextTshs.get(path);
		if (cache !== undefined) {
			const resolved = getResolvedTimestamp(cache);
			if (resolved !== undefined) return callback(null, resolved);
			return this._resolveContextTsh(cache, callback);
		}
		this.contextTshQueue.add(path, (err, _entry) => {
			if (err) return callback(err);
			const entry = /** @type {ContextTimestampAndHash} */ (_entry);
			const resolved = getResolvedTimestamp(entry);
			if (resolved !== undefined) return callback(null, resolved);
			this._resolveContextTsh(entry, callback);
		});
	}
@param {string} path context path
@param {(err?: WebpackError | null, resolvedContextTimestampAndHash?: ResolvedContextTimestampAndHash | null) => void} callback callback function
@returns {void}