// UUID Formats:
//
// a - time-low
// b - time-mid
// c - time-high-and-version
// d - clock-seq-and-reserved
// e - clock-seq-low
// f - node
//
// aaaaaaaa-bbbb-cccc-ddee-ffffffffffff
//               |    |
//               |    + 0 x x = NCS backward compat
//               |    + 1 0 x = This specification
//               |    + 1 1 0 = Reserved, Microsoft
//               |    + 1 1 1 = Reserved for future
//               |
//               + 0 0 0 1 = Time-based
//               + 0 0 1 0 = DCE Security
//               + 0 0 1 1 = Name Based (md5)
//               + 0 1 0 0 = Random
//               + 0 1 0 1 = Name Based (sha1)
//
//
// Version 1 - timestamp is count of 100-nanosecond intervals
//             since 00:00:00.00, 15 October 1582
//             - Clock seq is 14 bit variance number
//             - Node is Mac Address
// Version 4 - timestamp is random
//           - clock seq is 14 bit random number
//           - node is 48 bit random
// Version 3 &
// Version 5 - timestamp generated from a 'name'
//           - clock seq is generated from a 'name'
//           - node is generated from a 'name'