code: function loadModule(loader, name, options) {
      return new Promise(asyncStartLoadPartwayThrough({
        step: options.address ? 'fetch' : 'locate',
        loader: loader,
        moduleName: name,
        // allow metadata for import https://bugs.ecmascript.org/show_bug.cgi?id=3091
        moduleMetadata: options && options.metadata || {},
        moduleSource: options.source,
        moduleAddress: options.address
      }));
    }
docs: 15.2.4 15.2.4.1