docs: private boolean validateJoinRequest(JoinRequest joinRequest, Address target) {
          if (clusterService.isMaster()) {
              try {
                  node.getNodeExtension().validateJoinRequest(joinRequest);
              } catch (Exception e) {
                  logger.warning(e.getMessage());
                  nodeEngine.getOperationService().send(new BeforeJoinCheckFailureOp(e.getMessage()), target);
                  return false;
              }
          }
          return true;
      }