docs: function resolveExternal (parser, options) {
    if (!options.resolve.external) {
      // Nothing to resolve, so exit early
      return Promise.resolve();
    }
  
    try {
      // console.log('Resolving $ref pointers in %s', parser.$refs._root$Ref.path);
      var promises = crawl(parser.schema, parser.$refs._root$Ref.path + "#", parser.$refs, options);
      return Promise.all(promises);
    }
    catch (e) {
      return Promise.reject(e);
    }
  }