Maestro is great. However it lacks so many important features you might need

For example, Maestro does not let you to coordinate multiple flow tests together. One test case I had is one phone initiating a call, and another answers it. Instead, Maestro prefers that every flow is self contained and will not run both in parallel reliably

I found many such limitations in its design only after writing a whole lot of their custom flow syntax

> perhaps that syscall requires elevated privileges itself..?

You are exactly right

That's very interesting!

I'll try out IPv6

If you want to play with packet sockets you might find my notebook useful where I was going to implement TCP/IP from scratch (well, from layer 2 up): https://github.com/georgek/notebooks/blob/master/internet.ip... I did ICMP over IP but got bored before I got to TCP, though (it's way more complicated than IP). You could drop in your custom protocol in place of ICMP.

> The most popular encoding we use is called Unicode

Unicode is a character set, not an encoding UTF-8, UTF-16, etc. are encodings of that character set