StdioConfig File Pipes

[Aidan63]

The StdioConfig type allows you to ignore or pipe output from a process, but there are also two extra ones to pipe straight to a file path or an already opened file. Why are files the ones allowed here, what if I want to pipe straight out of a socket, or what if I want to pipe straight into my own custom IWritable. It seems odd that file is the only special case here.

We could add extra config options for these other cases but at that point it might be better to provide a more generic pipe mechanism as currently the user can't, say, automatically send a file through a socket. This would also greately reduce the complexity of the process implementation.

Alternatively don't provde any fancy pipe stuff and let the user do it themselves.