code: public static RequestQueue newRequestQueue(File cacheLocation, HttpStack stack) {
  
          File cacheDir = null;
          if (cacheLocation != null) {
              cacheDir = new File(cacheLocation, DEFAULT_CACHE_DIR);
          }
  
          String userAgent = "jus/0";
  
          if (stack == null) {
              stack = new HurlStack();
          }
  
          Network network = new HttpNetwork(stack);
  
          Cache cache = null;
  
          if(cacheDir!=null) {
              cache = new DiskBasedCache(cacheDir);
          } else {
              cache =  new NoCache();
          }
  
  
          RequestQueue queue = new RequestQueue(cache, network);
          queue.start();
  
          return queue;
      }
docs: Creates a default instance of the worker pool and calls {@link RequestQueue#start()} on it.
  
  @param cacheLocation A {@link File} 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.