How to start sending to clients with GOP packages (SPS, PPS, I-FRAME)

I used [example/rtsp_h264_file.cpp](https://github.com/PHZ76/RtspServer/tree/master/example/rtsp_h264_file.cpp) as an example, but I want the server to start sending data to connected clients with GOP (including SPS, PPS and I-FRAME). How can I do that?

Maybe I should skip the data until I find the packets I need, or somehow I can control the source/parser or connection for each client.

