Get the exact system date and time as a Temporal.Instant.

This method gets the current exact system time, without regard to calendar or time zone. This is a good way to get a timestamp for an event, for example. It works like the old-style JavaScript Date.now(), but with nanosecond precision instead of milliseconds.

Note that a Temporal.Instant doesn't know about time zones. For the exact time in a specific time zone, use Temporal.Now.zonedDateTimeISO or Temporal.Now.zonedDateTime.