code: public static LearningPushHandler learningPushHandler(int maxEntries, int maxAge, HttpHandler next) {
          return new LearningPushHandler(maxEntries, maxAge, next);
      }
docs: Creates a handler that automatically learns which resources to push based on the referer header
  
  @param maxEntries The maximum number of entries to store
  @param maxAge The maximum age of the entries
  @param next The next handler
  @return A caching push handler