code: public boolean skipUntil(long txid) throws IOException {
      while (true) {
        FSEditLogOp op = readOp();
        if (op == null) {
          return false;
        }
        if (op.getTransactionId() >= txid) {
          cachedOp = op;
          return true;
        }
      }
    }
docs: Skip edit log operations up to a given transaction ID, or until the
  end of the edit log is reached.
  
  After this function returns, the next call to readOp will return either
  end-of-file (null) or a transaction with a txid equal to or higher than
  the one we asked for.
  
  @param txid    The transaction ID to read up until.
  @return        Returns true if we found a transaction ID greater than
  or equal to 'txid' in the log.