This demonstates serving both normal content and content over Server Side Events.
$ cmake . && make
You can give -s to listen using https on port :443
$ ./lws-minimal-http-server-sse [2018/04/20 06:09:56:9974] USER: LWS minimal http Server-Side Events | visit http://localhost:7681 [2018/04/20 06:09:57:0148] NOTICE: Creating Vhost 'default' port 7681, 2 protocols, IPv6 off
Visit http://localhost:7681, which connects back to the server using SSE and displays the incoming data. Connecting from multiple browsers shows content individual to the connection.