code: public static HttpURLConnection toHttpConnection(Collection<Request> requests) {
          Validate.notEmptyAndContainsNoNulls(requests, "requests");
  
          return toHttpConnection(new RequestBatch(requests));
      }
docs: Serializes one or more requests but does not execute them. The resulting HttpURLConnection can be executed
  explicitly by the caller.
  
  @param requests
  one or more Requests to serialize
  @return an HttpURLConnection which is ready to execute
  
  @throws FacebookException
  If any of the requests in the batch are badly constructed or if there are problems
  contacting the service
  @throws IllegalArgumentException if the passed in collection is empty
  @throws NullPointerException if the passed in collection or any of its contents are null