Get the current calendar date and clock time in a specific calendar and time zone.

The calendar is required. When using the ISO 8601 calendar or if you don't understand the need for or implications of a calendar, then a more ergonomic alternative to this method is Temporal.Now.plainDateTimeISO.

Note that the Temporal.PlainDateTime type does not persist the time zone, but retaining the time zone is required for most time-zone-related use cases. Therefore, it's usually recommended to use Temporal.Now.zonedDateTimeISO or Temporal.Now.zonedDateTime instead of this function.