code: public void setCommittedTxId(long txid, boolean force) {
      for (AsyncLogger logger : loggers) {
        logger.setCommittedTxId(txid, force);
      }
    }
docs: Set the highest successfully committed txid seen by the writer.
  This should be called after a successful write to a quorum, and is used
  for extra sanity checks against the protocol. See HDFS-3863.