Class not found for a new module/service I am building. I am not sure how to debug
And this is my class
/modules/custom/fivewire_commerce/EventSubscriber/fivewire_commerce_orderStateSubscriber.php

Autoloading relies on your classes being in a root /src folder for the module.
So move the file to

/modules/custom/fivewire_commerce/src/EventSubscriber/fivewire_commerce_orderStateSubscriber.php

And PHP will be able to find it.