public static (long ticks, long offset) Parse(FormatParser formatParser, string format, string value)
{
var formats = formatParser.ParseSpecifiers(format);
var chunks = Parse(formats, value);
var(days, hours, minutes, seconds, ds, cs, ms, tts, hts, micros, tick, pm) =
(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, false);
var(year, month) = (0, 0);
var offset = 0L;
var negate = false;
foreach (var(kind, val) in chunks)
{
switch (kind)
{
case Sign:
negate = val == "-";
break;
case Offset:
{
if (val.Length == 0)
{
throw new FormatException();
}
var sign = val[0];
var sval = val[1..];