How to use the api-spec-converter.ResourceReaders function in api-spec-converter

}

function getCacheEntry(url) {
  var cacheIndex =_.findIndex(httpCache.cache,function(e){
    return e.url === url;
  });
  if (cacheIndex>=0)
    return httpCache.cache[cacheIndex];
  else {
    var cacheEntry = { url: url };
    httpCache.cache.push(cacheEntry);
    return cacheEntry;
  }
}

converter.ResourceReaders.url = function (url) {
  resolverContext.called = true;
  var options = {
    headers: {
      'Accept': 'application/json,*/*',
      'Accept-Language': 'en-GB,en;q=0.5'
    },
  retries : 10
  };
  var cacheEntry = getCacheEntry(url);
  if (cacheEntry && cacheEntry.etag && resolverContext.etag && resolverContext.format !== 'swagger_1') {
    options.headers['If-None-Match'] = cacheEntry.etag;
  }
  return makeRequest('get', url, options)
    .then(function(result){
      if (result[0].statusCode === 304) {
    throw new Error('Warning: 304 Not Modified');