code: public EtcdKeyPutRequest refresh(String key, Integer ttl) {
      return new EtcdKeyPutRequest(client, key, retryHandler).refresh(ttl);
    }
docs: Refresh a key with new ttl
  (without notifying watchers when using etcd 2.3+)
  
  @param key to refresh
  @param ttl to update key with
  @return EtcdKeysRequest