This section discusses mppopmd command syntax & will be of
interest only to authors of MPD clients that want to communicate
with mppopmd.
Clients can invoke mppopmd commands via the
sendmessage MPD command to the mppopmd commands channel, e.g.
$>: nc localhost 6600 OK MPD 0.22.0 sendmessage unwoundstack.com:commands "rate 255" OK