code: public void keepAliveSessions(long index, long timestamp) {
      log.debug("Resetting session timeouts");
  
      this.currentIndex = index;
      this.currentTimestamp = Math.max(currentTimestamp, timestamp);
  
      for (RaftSession session : sessions.getSessions(primitiveId)) {
        session.setLastUpdated(timestamp);
      }
    }
docs: Keeps all sessions alive using the given timestamp.
  
  @param index     the index of the timestamp
  @param timestamp the timestamp with which to reset session timeouts