Communicating Sequential Processes (CSP) is a way of modelling the interaction between concurrent processes or threads.

Go's channels support CSP semantics for communicating and synchronising between Go-routines.

BusterWood.Channels supports CSP semantics for communicating and synchronising between (logical async/await) threads in .NET.

Some messaging systems support CSP semantics, for example, in MSMQ you can send a message and wait for the destination process to receive the message by waiting for acknowledgement via an administration queue.