[carapace]

"async" is BS. You can't smear concurrency over your systems like Nutella.

Read "Communicating Sequential Processes" by Tony Hoare https://www.cs.cmu.edu/~crary/819-f09/Hoare78.pdf

There's also a book: http://www.usingcsp.com/

See also https://en.wikipedia.org/wiki/Process_calculus