This is based on the prototype derived from the meeting at the DMSC last December.

The workflow is as follows:
  - Pool all events received from the Kafka stream into a single buffer
  - When the buffer is to be flushed (i.e. events populated in the EventWorkspace):
    - Parallel sort the event buffer by the detector ID/workspace index
    - Determine group boundaries
    - Parallel insert events into EventWorkspace

Also included is the optimisation of using a spec to ID mapping based on
a vector rather than map.
This provides better performance during the initial event buffering
(where this lookup is made).

Initial benchamrking shows 25M events is a intermediate buffer threshold
for LOKI (9 banks) at 10^7 events per second.
This manages to maintain well over 14Hz pulse rate (with no post
processing).