How to end the child process when the program exits?

[OneSeven]

I cannot execute exec.Command in startup,
I run exec.Command before wails.run,
So how to end the child process when the program exits? Calling cmd.Process.Kill() in shutdown will throw an error

[1105/175936.134:ERROR:window_impl.cc(114)] Failed to unregister class Chrome_WidgetWin_0. Error = 0

[OneSeven]

I need to test again