Serial over network via socat

From http://www.anites.com/2017/11/socat.html:

on remote:
  socat tcp-listen:8000,reuseaddr,fork \
    file:/dev/ttyUSB0,nonblock,waitlock=/var/run/tty0.lock,b115200,raw,echo=0

on local:
  socat pty,link=/dev/ttyUSB0,waitslave tcp:pi.local:8000
  tio -b 115200 /dev/ttyUSB0