code: private synchronized void renewDelegationToken() throws IOException, InterruptedException {
      this.token.renew(this.fs.getConf());
      writeDelegationTokenToFile();
  
      if (!this.firstLogin) {
        // Send a message to the controller and all the participants if this is not the first login
        sendTokenFileUpdatedMessage(InstanceType.CONTROLLER);
        sendTokenFileUpdatedMessage(InstanceType.PARTICIPANT);
      }
    }
docs: Renew the existing delegation token.