property Temporal.DurationArithmeticOptions.relativeTo
The starting point to use when variable-length units (years, months,
weeks depending on the calendar) are involved. This option is required if
either of the durations has a nonzero value for `weeks` or larger units.
This value must be either a `Temporal.PlainDateTime`, a
`Temporal.ZonedDateTime`, or a string or object value that can be passed
to `from()` of those types. Examples:
- `'2020-01-01T00:00-08:00[America/Los_Angeles]'`
- `'2020-01-01'`
- `Temporal.PlainDate.from('2020-01-01')`
`Temporal.ZonedDateTime` will be tried first because it's more
specific, with `Temporal.PlainDateTime` as a fallback.
If the value resolves to a `Temporal.ZonedDateTime`, then operation will
adjust for DST and other time zone transitions. Otherwise (including if
this option is omitted), then the operation will ignore time zone
transitions and all days will be assumed to be 24 hours long.