Complete Gossip handover

[rogeralsing]

Currently we are running with half the Gossip only. e.g. Member A sends gossip to member B Member B acks "OK"

The full flow should be

Member A sends gossip to member B Member B sends its' state back to A Member A sends a final Ack to complete the flow.

This allows for a faster convergence of the gossip state than the current approach