Better sending of PSN packets

[m-tthw]

Hey,

So I rebased, updated the pytest you created to better cover my new code and did extensive testing on Raspberry Pi / macOS to GrandMA3.

Features added since then:

• Handling the infamous bit-32 PSN_CHUNK_HEADER / has_subchunks in sent PSN packets.
• Unicast mode if no multicast IP provided (improves stability in complex networks).

Everything looks good and stable to me now. I hope I didn't forget any detail in order to merge to your project :)

Let me know, thank you for your time!

[vanous]

Sounds good 👍, thank you! I will check it out.

[vanous]

I tested this with BlenderDMX - using the example sender sending PSN data via multicast from one computer and receiving it on another computer with default BlenderDMX address being 0.0.0.0 and it worked :) So i will merge. I will squash the commits, to keep the history in the PR and have a clean commit in master, hope you are OK with that :)

One point of friction to mention is the multicast_expert. It depends on netifaces but that is requiring specific platform build and as netifaces is deprecated, there are no wheels for new pythons, making installation hard. The way i deal with that in BlenderDMX is by using pure python based libs, like ifaddr. Maybe it would be good to try to open an issue with the multicast_expert maintainer, to try to switch to other library to get the network interfaces without requiring netifaces?

[m-tthw]

Thanks!

Agreed for multicast expert. I'd like to do without in the future. I'll let you know once I find a workaround :)