Your analogy is better directed towards the bsd sockets API that 99% of programs use, rather than TCP itself. I still feel that the API should lean even further

Your analogy is better directed towards the bsd sockets API that 99% of programs use, rather than TCP itself. I still feel that the API should lean even further into the "two streams" abstraction, as described here: http://cr.yp.to/tcpip/twofd.html http://cr.yp.to/tcpip/twofd.html