code: private void startRecording(String line, DispatchCallback callback) {
      OutputFile outputFile = sqlLine.getRecordOutputFile();
      if (outputFile != null) {
        callback.setToFailure();
        sqlLine.error(sqlLine.loc("record-already-running", outputFile));
        return;
      }
  
      String filename;
      if (line.length() == "record".length()
          || (filename =
              sqlLine.dequote(line.substring("record".length() + 1))) == null) {
        sqlLine.error("Usage: record <file name>");
        callback.setToFailure();
        return;
      }
  
      try {
        outputFile = new OutputFile(expand(filename));
        sqlLine.setRecordOutputFile(outputFile);
        sqlLine.output(sqlLine.loc("record-started", outputFile));
        callback.setToSuccess();
      } catch (Exception e) {
        callback.setToFailure();
        sqlLine.error(e);
      }
    }
docs: Start writing to the specified record file.