With a configuration option, the following function is available which opens
streams across network connections.
— Function: open-client-stream host port
The string host indicates the name of the host, while port is an
integer which identifies the port number to which to connect. This function
returns a two-way stream which can be used in any of the stream operations.
— Function: open-server-stream host port
A stream connected to port number port is created to which clients can
connect. This function returns a two-way stream which can be used in any of
the stream operations.