Handle participant states based on session expiry events

[junkaixue]

Copied from Imran email :

I have a helix cluster setup with a resource in MASTER-SLAVE configuration with 3 replicas. We are testing what happens when a client temporarily looses network connectivity to the ZK cluster. The observations are:

1. The client continues to think it is MASTER (DISCONNECT event is triggered in the background and reconnecting messages are seen)
2. The controller makes another node MASTER
3. Once the client is able to reconnect a session expired is triggered, and reset is called on the MASTER-SLAVE, moving the partitions to OFFLINE state.

I would like the node to stop serving requests as MASTER as soon as client detects that session expiration timeout has passed even though the session may not be expired. Curator framework injects a session timeout event based on percent of the negotiated timeout, and I was hoping that in Helix something similar could be configured. Otherwise there is a state where multiple nodes think they are masters.