Do a check if any exit handlers have been registered by someone else.
If not, will set up exit handlers to ensure child processes are killed on exit signal.
NO
NO = 0
Don't set up any exit handlers (depending on your environment and Node version,
children might need to be manually killed).
YES
YES = 1
Set up exit handlers to ensure child processes are killed on exit signal.
Do a check if any exit handlers have been registered by someone else. If not, will set up exit handlers to ensure child processes are killed on exit signal.