How does direction_control for vacuums work in HA?

[blakadder]

direction_control (optional, mapping of strings): a dp that is used for directional commands These are additional commands that are not part of status. They can be sent as general commands from HA.

How does this work in context of HA? I assume it's with the service vacuum.send_command but it's not clear how exactly

[make-all]

They are used through the vacuum.send_command service call with the mapped value given as command.

[blakadder]

For reference:

service: vacuum.send_command
data: 
  entity_id: vacuum.m9_robot_vacuum
  command: forward

UI example: