Seems like the same as in multithreaded programming, in which you can’t let threads share memory without synchronizing else you get data races and corruption.
it's more like two simple computers talking over serial, and the serial connection bitrate can't be faster than the clock of the slowest of the two computers.
I hope they can avoid having two block indents, like in those examples. Match could be followed by a case in the same line, and extra cases in new lines.
match val case True:
print("Ok")
case False:
print("Not ok")
print("Done")