def timestamp
      return nil if self.version != 1
      gmt_timestamp_100_nanoseconds = 0
      gmt_timestamp_100_nanoseconds +=
        ((self.time_hi_and_version  & 0x0FFF) << 48)
      gmt_timestamp_100_nanoseconds += (self.time_mid << 32)
      gmt_timestamp_100_nanoseconds += self.time_low
      return Time.at(
        (gmt_timestamp_100_nanoseconds - 0x01B21DD213814000) / 10000000.0)
    end
def timestamp
      return nil if self.version != 1
      gmt_timestamp_100_nanoseconds = 0
      gmt_timestamp_100_nanoseconds +=
        ((self.time_hi_and_version  & 0x0FFF) << 48)
      gmt_timestamp_100_nanoseconds += (self.time_mid << 32)
      gmt_timestamp_100_nanoseconds += self.time_low
      return Time.at(
        (gmt_timestamp_100_nanoseconds - 0x01B21DD213814000) / 10000000.0)
    end
Returns the timestamp used to generate this UUID