Why Kino.listen doesn't return a pid?

[Jannik Becher]

kino/lib/kino.ex

Lines 419 to 428 in 78e58cf

 defp async(fun) do 
   {:ok, _pid} = 
     Kino.start_child(%{ 
       id: Task, 
       start: {Kino.Terminator, :start_task, [self(), fun]}, 
       restart: :temporary 
     }) 
  
   :ok 
 end 

Is there a specific reason why :ok is returned instead of the pid?
It would be nice to be able to do something like this:

job_pid = Kino.listen(5000, fn i -> IO.puts(i) end)

Kino.Control.button("Kill job")
|> Kino.render()
|> Kino.listen(fn _ -> Process.exit(job_pid, :kill) end)

[José Valim]

Can you please send a PR?

[Jannik Becher]

Just for reference:
Process.exit(job_pid, :kill) kills the whole cell. Instead use Kino.terminate_child(job_pid)