How can you guarantee that? NTP fails to guarantee that all clocks are synced inside a datacenter, let alone across an ocean (Did not read the code yet)
EDIT: The wording got me. "Guarantee" & "Perfect" in the post title, and "Millisecond-accurate synchronization" in the README. Cool project!
Going off on a tangent: Back in the days of Live Aid, they tried doing a transatlantic duet. Turns out it’s literally physically impossible because if A songs when they hear B, then B hears A at least 38ms too late, which is too much for the human body to handle and still make music.
That's assuming standard OS and hardware and drivers can manage latency with that degree of precision, which I have serious doubts about.
In a duet, your partner needs to hear you now and you need to hear them now. With pre-recorded audio, you can buffer into the future.
If you _don’t_ have real time communication, then you don’t really need to solve this problem. But the problem is fundamentally unsolvable because the speed of light (in a vacuum) is the speed of causality and, as I say, puts a hard cap on simultaneity. This tends to be regarded as obvious at interstellar distances but it affects us at transatlantic distances too.
Also latency demands on conversation are not nearly as tight as those on music performance. See ubiquitous video conferences.
Special relativity does indeed have something to say about simultaneity.
> Wolfram Alpha reckons New York to London is 19ms in a vacuum, more using fibre.
And this is not, in any respect, a limit on simultaneity. If the endpoints are moving at very very very quickly relative to each other, then there are complications. Otherwise you measure that 19ms or so and deal with it.