code: public static RequestQueue newRequestQueue(Context context, HttpStack stack) {
          JusLog.log = new ALog();
          File cacheDir = new File(context.getCacheDir(), DEFAULT_CACHE_DIR);
          String userAgent = "jus/0";
          try {
              String packageName = context.getPackageName();
              PackageInfo info = context.getPackageManager().getPackageInfo(packageName, 0);
              userAgent = packageName + "/" + info.versionCode;
          } catch (NameNotFoundException e) {
          }
  
          if (stack == null) {
              stack = new HurlStack();
          }
  
          Network network = new HttpNetwork(stack);
  
          RequestQueue queue = new RequestQueue(new DiskBasedCache(cacheDir), network,
                  RequestQueue.DEFAULT_NETWORK_THREAD_POOL_SIZE,
                  new AndroidExecutorDelivery(new Handler(Looper.getMainLooper())));
          queue.withCacheDispatcher(
                  new AndroidCacheDispatcher(
                          queue.cacheQueue, queue.networkQueue, queue.cache,
                          queue.delivery))
                  .withNetworkDispatcherFactory(
                          new AndroidNetworkDispatcher.NetworkDispatcherFactory(
                                  queue.networkQueue, queue.network,
                                  queue.cache, queue.delivery));
          queue.start();
  
          return queue;
      }
docs: Creates a default instance of the worker pool and calls {@link RequestQueue#start()} on it.
  
  @param context A {@link Context} to use for creating the cache dir.
  @param stack   An {@link HttpStack} to use for the network, or null for default.
  @return A started {@link RequestQueue} instance.