Start SSE stream from last message by default

[vordimous]

Describe the desired outcome from the user's perspective As an HTTP client, I want to connect to an SSE stream that starts after the last known message. A client that can't handle historical data or is loading from a server-side rendered page or similar dataset can't resolve conflicts and wants to avoid rendering duplicate messages. This client may only want new messages that come in after connecting to the stream.

Acceptance criteria

• Add an option for an SSE stream to dynamically start from the next live message when the client connects

[pnikhil610]

I wanted to raise another concern. I'm not totally sure if this is related to this issue.

Here's the issue I'm facing. Let's say I have kafka topic with lots of messages. Let's say our topic is compacted. I have a SSE endpoint which filters keywise data passed through query params.

Whenever zilla is restarted, if a client is already connected, zilla starts sending all compacted data for that key in the topic.

Something like waiting for zilla to be rebalanced with Kafka before sending updates would be helpful when starting up.