code: public static <K, V> ConcurrentMap<K, V> getMapRequestAttribute(
              ServletRequest servletRequest, String name) {
          return getMapRequestAttribute(servletRequest, name, true);
      }
docs: Get a {@link ConcurrentMap} for the specified name from the {@link ServletRequest}
  attributes. If it doesn't exist create it and store it in the attributes. This is done in a
  thread-safe matter that ensures only one Map per name & request will be created @See {@link
  #getRequestAttributeMutex(ServletRequest)}