Hello,
We do not have such feature implemented yet. It can be implemented for RTMP but I’m not entirely sure about HLS (iOS). Same goes for RTSP. HDS is having big chances of supporting it because is nothing more than a special FLV file so that could be done through cue points. However, is highly dependent on the player implementation
I will come back with more details about a possible roadmap for this feature
Best regards,
Andrei