Converts this date-time to an {@code Instant}.
!(p)
This returns an {@code Instant} representing the same point on the
time-line as this date-time. The calculation combines the
{@linkplain #toLocalDateTime() local date-time} and
{@linkplain #getOffset() offset}.
@return an {@code Instant} representing the same instant, not null
Converts this date-time to an {@code Instant}. !(p) This returns an {@code Instant} representing the same point on the time-line as this date-time. The calculation combines the {@linkplain #toLocalDateTime() local date-time} and {@linkplain #getOffset() offset}.
@return an {@code Instant} representing the same instant, not null