[racket] `subprocess' and `file-stream-port?'

At Fri, 22 Mar 2013 12:49:07 -0300, Diogo F. S. Ramos wrote:
> `subprocess' only accepts ports that are also `file-stream-port?'.
> 
> Is there a reason for it?

The argument ports are effectively passed on to the OS, which can only
deal with file-stream ports.

The `process*/ports' function from `racket/system' can deal with any
kind of port, and it creates a thread to transfer data as needed.