Correct. Progressive MP4 also do the trick. Many open-source tool such as ffmpeg (generalist), gpac (specialized in this and leveraging ffmpeg), etc. in the area.
> I've heard from colleagues that this won't be possible with DASH due to the switch to fMP4 format.
That's incorrect. With DASH the latency depends on the fragment duration, not the segment duration. You can start sending the segment when its first fragment is generated, and use chunk-based HTTP transfer as mentioned in other comments.