Pretending known chardata is an I/O device?

[Yestin L. Harrison]

Say I have some black box that expects some IO server to read from; what is the recommended way of spawning such a server that can just be passed some string/chardata()/binary/whatever and serve it in response to io:request(...)? Am I going to have to write something like that myself or is there something in the standard libraries that I'm missing?