Define and Implement Application-level Event Notifications

[dixonwhitmire]

Investigate the use of LFH events for application-level consumers.

Today, application-level clients subscribe to data synchronization messages from multiple NATS servers in a LinuxForHealth network, the same way that LinuxForHealth nodes subscribe to multiple NATS servers.

Instead, an application-level client should be able to subscribe to a single LinuxForHealth node and get all data synchronization messages, which would cut down on both code and network traffic.

To do this, implement an application-level data synchronization message. To emit this message, a LinuxForHealth node would receive or generate a sync message, then emit an application sync message with the same content. That application sync message is what application-level clients subscribe to in order to receive sync messages from all nodes in the LinuxForHealth network.