code: protected void handleMailCount(ActionRuntime runtime) {
          if (ThreadCacheContext.exists()) {
              final PostedMailCounter counter = ThreadCacheContext.findMailCounter();
              if (counter != null) {
                  saveRequestedMailCount(counter);
              }
          }
      }
docs: Handle count of mail posting in the request.
  @param runtime The runtime meta of action execute. (NotNull)