That 15 second lag is related to the network buffering, and would happen inside a muxer as well as outside. A muxer may add another layer of buffering, but I find that you can typically clear it out faster by switching to another window then back, so the output doesn’t need to be sent over the network.
That's a very good point. There is the entire Linux network stack in the way, and the Hyper-V virtual network driver, and the Windows networking stack.
In like 2008 I was using a Perl library that was all about zero-copy networking. That is not what this is.
