srecord noeq FollowTickerFile(File tickerFile) is AutoCloseable {
  settable int historyEntriesToGrab;

  // internal, may change  
  TailFile tailFile;
  
  event historicLine(S line);
  event liveLine(S line);
  
  settable int maxLineLengthForTickerEntry = 200;

  void start {
    long fileSize = l(tickerFile);
    long start = max(0, fileSize-maxLineLengthForTickerEntry*historyEntriesToGrab);
    S text = loadTextFilePart(tickerFile, start, fileSize);
    LS lastTickerLines = takeLast(historyEntriesToGrab, lines(text));

    for (line : lastTickerLines)
      historicLine(line);
  
    tailFile = tailFileLinewiseFromPosition(tickerFile, 250, fileSize, l0 liveLine);
  }
  
  close {
    dispose tailFile;
  }
}