Push notification for specific person with Server Sent Event

Hi,

I am trying with SSE to send newest update from server to browser. It is need identify for specific client.
i see https://stackoverflow.com/questions/45160864/play-framework-and-server-side-events-or-websocket-for-specific-client but no useful answer.

I found this project https://github.com/ariel7342/java-play-2.5

My question is how to assign a subcribser with my generated id. Thanks so much.