There seems to be something interesting going on in the SSE/pubsub plugin where:

• SSE connections are opened/closed every thirty seconds
• During this time some events are not replayed to the client on reconnect and events are lost
  • To reproduce: have two browser windows open on the Activity screen running/stopping pipelines - things will go out of sync particularly around reconnects).
  • I think we open and close so often because there is no "heartbeat" back to the server

I am not sure if these modules are following our new standards for code quality either.

We need to:

• Get to the bottom of the lost events
• Introduce a heart beat to reduce reconnections every 30 secons
• Analyse test coverage
• Relook at how threads are being serialized (lots of usages of synchronized)
• Ensure that we improve the quality around replay.
• Make these modules more testible