Detect End of Line from file. changed from : https://stackoverflow.com/questions/25853504/c-sharp-determine-eol-character-in-flat-files

DetectEol.cs

public static class DetectEndOfLine
{
    public static EndOfLineStyle Detect(string pathToFile)
    {
        int bufl = 0;
        var buf = ArrayPool<char>.Shared.Rent(8192);
        try
        {
            return DetectCore(pathToFile, buf, bufl);
        }
        finally
        {
            ArrayPool<char>.Shared.Return(buf);
        }
    }

    private static EndOfLineStyle DetectCore(string pathToFile, char[] buf, int bufl)
    {
        using (var reader = File.OpenText(pathToFile))
        {
            bufl = reader.ReadBlock(buf, 0, buf.Length);
        }

        var (crlf, cr, lf) = (0, 0, 0);
        for (int i = 0; i < bufl;)
        {
            if (buf[i] == '\r' && i < bufl - 1 && buf[i + 1] == '\n') { ++crlf; i += 2; }
            else if (buf[i] == '\r') { ++cr; i += 1; }
            else if (buf[i] == '\n') { ++lf; i += 1; }
            else { i++; }
        }

        EndOfLineStyle style;
        if (crlf > cr && crlf > lf) style = EndOfLineStyle.Windows;
        else if (lf > crlf && lf > cr) style = EndOfLineStyle.Unix;
        else if (cr > crlf && cr > lf) style = EndOfLineStyle.MacOs;
        else style = EndOfLineStyle.Unknown;

        return style;
    }

    public enum EndOfLineStyle
    {
        Unknown = 0,
        CR = 1,
        LF = 2,
        CRLF = CR | LF,
        Unix = LF,
        MacOs = CR,
        Windows = CRLF,
    }
}