Now size could mark last read position, record the file size we read last time is enough.

If time zone not match, date time compare is not available.

How about set time zone in file getter?

No increment for a old file, marker also re-save the Json.

I'll crazy for this!!!

May be occurred by machine restart.

Usually we want time range data to report

Now code is following:
// get increatation lines
//
var res = allLines.GetRange(marker.GetSplitIndex(detail.Item3), count);
if (applyNewData(res))
{
marker.Set(detail.Item3, detail.Item1, detail.Item2, splitIdx);
FileMarkerManager.Save(marker);
}
else
{
errors.Add(string.Format("Applying error\t{0}", detail.Item3));
}
}
catch(Exception e)
{
errors.Add(string.Format("Reading error\t{0}\t{1}", detail.Item3,e.Message));
}

The Exception e will catch all exceptions when applying data and reading data, so the method applyNewData needn't to have a return value, it just be void is OK.

After using FileUnitIncreatationFilter, the last one will be missed in Merage(IEnumerable origin, string splitPattern) function.

When program calling StreamReader.ReadToEnd method, it is asking for a continuous memory from the local machine, if the machine couldn't offer the enough memory, the System.IO.OutOffMemeoryException will be thrown.

Json.net need to reflect the FileMarkerManager with default ctor

The architecture should be following:
Interface -> abstract class -> implementation class

The service cannot wait when server shut down, so need to stop immediately.