Returns an instant that corresponds to this civil date/time value in the time zone provided as an implicit receiver.
Note that the conversion is not always unambiguous. There can be the following possible situations:
There's only one instant that has this date/time value in the time zone. In this case the conversion is unambiguous.
There's no instant that has this date/time value in the time zone. Such situation appears when the time zone experiences a transition from a lesser to a greater offset. In this case the conversion is performed with the lesser offset.
There are two possible instants that can have this date/time components in the time zone. In this case the earlier instant is returned.