> But there's no checking of the sequencing of communications (e.g. you
> can't specify that SYN in one direction is followed by ACK in the other).
there was a variant that did more than that, using a protocol description
based on regular expressions, by the late A J Fisher (University of York)
it included compile-time checking.
Fisher A J 1988 A critique of OCCAM channel types. Computer Languages
13(2) 95-105
it's also discussed in another article to supply a theoretical basis
Carlisle W H, Type Checking Concurrent I/O, TOPLAS 17(3) 445-469
