code: def spawn_isolated_child(econtext):
      
      mitogen.parent.upgrade_router(econtext)
      if FORK_SUPPORTED:
          context = econtext.router.fork()
      else:
          context = econtext.router.local()
      LOG.debug('create_fork_child() -> %r', context)
      return context
docs: For helper functions executed in the fork parent context, arrange for
      the context's router to be upgraded as necessary and for a new child to be
      prepared.
  
      The actual fork occurs from the 'virginal fork parent', which does not have
      any Ansible modules loaded prior to fork, to avoid conflicts resulting from
      custom module_utils paths.