Parsing subtitle using AngleSharp/State tecni

// Parsing JacoSub (subtitle edit)

private struct ParseData
        {
            public TimeSpan StartTime { get; set; }
            public TimeSpan EndTime { get; set; }
        }

        Paragraph Paragraph(string line)
        {
            return StartTime(line, 0);
        }

        Paragraph StartTime(string line, int position)
        {
            var parseData = new ParseData();
            // H:MM:SS.FF H:MM:SS.FF directive {comment} text {comment} more text...
            if (position + 10 < line.Length)
            {
                var timestamp = line.Substring(position, 10);
                parseData.StartTime = TimeSpan.ParseExact(timestamp, "H:MM:SS.FF", CultureInfo.CurrentCulture);
                return EndTime(line, position + 10, ref parseData); // read the time cod from 10 index
            }

            return null;
        }

        Paragraph EndTime(string line, int position, ref ParseData parseData)
        {
            // H:MM:SS.FF H:MM:SS.FF directive {comment} text {comment} more text...
            while (position < line.Length && line[position] == ' ') position++;

            if (position + 10 < line.Length)
            {
                var timestamp = line.Substring(position, 10);
                parseData.EndTime = TimeSpan.ParseExact(timestamp, "H:MM:SS.FF", CultureInfo.CurrentCulture);
                return EndTime(line, position + 10, ref parseData); // read the time cod from 10 index
            }

            return null;
        }

        Paragraph Text(string line, int position, ref ParseData token)
        {
            // H:MM:SS.FF H:MM:SS.FF directive {comment} text {comment} more text...
            if (position + 1 < line.Length)
            {
                return new Paragraph()
                {
                    StartTime = new TimeCode(token.StartTime.TotalMilliseconds),
                    EndTime = new TimeCode(token.EndTime.TotalMilliseconds),
                    Text = line.Substring(position).TrimStart()
                };
            }

            return null;
        }