Add a new generator for GUIDs that generates GUIDs in ascending order. The algorithm will be similar to that for ObjectIds, and the 16 bytes of the GUID will be generated as follows:

8 bytes: Ticks from DateTime.UtcNow.Ticks
3 bytes: hash of machine name
2 bytes: low order bytes of process Id
3 bytes: increment

This is the same algorithm as generating an ObjectId except that a higher resolution 8 byte timestamp is used.

NOTE: in order for these GUIDs to be considered ascending by the server they must be stored using the new GuidRepresentation.Standard representation for GUIDs.