roundtrip property
Pattern which uses the normal ISO format for all the supported ISO fields, but extends the time part with 's' for milliseconds, "t" for ticks and "n" for nanoseconds. No normalization is carried out, and a period may contain weeks as well as years, months and days. Each element may also be negative, independently of other elements. This pattern round-trips its values: a parse/format cycle will produce an identical period, including units.
Pattern which uses the normal ISO format for all the supported ISO fields, but extends the time part with 's' for milliseconds, "t" for ticks and "n" for nanoseconds.
Implementation
static final PeriodPattern roundtrip = PeriodPattern._(_RoundtripPatternImpl());