def round(ndigits = 0)
      if_timezone_offset(super) {|o,t| self.class.at(t.to_i, t.subsec * 1_000_000).set_timezone_offset(o) }
    end
def round(ndigits = 0)
      if_timezone_offset(super) {|o,t| self.class.at(t.to_i, t.subsec * 1_000_000).set_timezone_offset(o) }
    end
An overridden version of `Time#round` that, if there is an associated
 {TimezoneOffset}, returns a {TimeWithOffset} preserving that offset.

 @return [Time] the rounded time.