how to get a post to stop loading on another post

[jimcollum]

Brand new user to swagger.
in one post window, i've started a network capture (tshark). The duration can be any number of seconds. I have a second post that i can use to stop a capture already in progress (initiated from the first capture post). Once I start the capture, the Loading icon with a black circle rotating around it begins. If I've specified duration of 10 seconds, then when that expires, the loading stops (as does the underlying process)
If I specify 1000 seconds, then try to stop it with the second post window, that works.. it stops the capture. Is there a way to send a msg to the first post to stop the 'loading'?