getSourceForEmptyContext(id, runtimeTemplate) {
		return `function webpackEmptyContext(req) {
	var e = new Error("Cannot find module '" + req + "'");
	e.code = 'MODULE_NOT_FOUND';
	throw e;
}
webpackEmptyContext.keys = ${runtimeTemplate.returningFunction("[]")};
webpackEmptyContext.resolve = webpackEmptyContext;
webpackEmptyContext.id = ${JSON.stringify(id)};
module.exports = webpackEmptyContext;`;
	}
@param {ModuleId} id module id
@param {RuntimeTemplate} runtimeTemplate runtime template
@returns {string} source for empty async context