plusTimespan method
Adds a Timespan.
var dt = LocalDateTime(2000, 1, 1);
var timespan = Timespan(days: 30, hours: 1);
dt.plusTimespan(timespan) == LocalDateTime(2000, 1, 31, 1);
Implementation
LocalDateTime plusTimespan(Timespan amount) =>
LocalDateTime._fromRataDieDate(_asTimespan + amount);