Send mavlink message no flight controller

I am trying to send a message via mavlink telemetry to control a servo on a jetson nano. I am not using a flight controller. I am using jetson.gpio to control the servo and just need the mavlink message to act as a trigger. Is this even possible to send a message from mavlink to mavlink not using a flight controller. I have been trying with the heartbeat message and mavproxy does successfully find a link but the message doesnt seem to be sending.

Start with the MAVLink heartbeat and MAVProxy link described in the issue, then check how pymavlink handles communication between endpoints without a flight controller. Reproduce the Jetson Nano setup if possible and determine whether a MAVLink message can trigger the jetson.gpio servo control; document the required configuration or confirm the limitation.

Written by the indexing model from the issue text.