_getManagedItemDirectoryInfo(path, callback) {
		this.fs.readdir(path, (err, elements) => {
			if (err) {
				if (err.code === "ENOENT" || err.code === "ENOTDIR") {
					return callback(null, EMPTY_SET);
				}
				return callback(/** @type {WebpackError} */ (err));
			}
			const set = new Set(
				/** @type {string[]} */ (elements).map(element =>
					join(this.fs, path, element)
				)
			);
			callback(null, set);
		});
	}
@private
@type {Processor<string, Set<string>>}