docs: public @CheckForNull Future<FormValidation> updateDirectly(final boolean signatureCheck) {
          if (! getDataFile().exists() || isDue()) {
              return Jenkins.getInstance().getUpdateCenter().updateService.submit(new Callable<FormValidation>() {
                  @Override public FormValidation call() throws Exception {
                      return updateDirectlyNow(signatureCheck);
                  }
              });
          } else {
              return null;
          }
      }