Also they bypass the 'single stdout' restriction

##### ISSUE TYPE
- Bug Report

##### COMPONENT NAME
<!--- Write the short name of the module, plugin, task or feature below, use your best guess if unsure -->
collections

##### ANSIBLE VERSION
<!--- Paste verbatim output from "ansible --version" between quotes -->
```paste below
2.8, 2.9
```

##### CONFIGURATION
<!--- Paste verbatim output from "ansible-config dump --only-changed" between quotes -->
```paste below

```

##### OS / ENVIRONMENT
<!--- Provide all relevant information below, e.g. target OS versions, network device firmware, etc. -->
any

##### STEPS TO REPRODUCE
<!--- Describe exactly how to reproduce the problem, using a minimal test-case -->
put callback into collection and whitelist
<!--- Paste example playbooks or commands between quotes below -->
```yaml

```

<!--- HINT: You can paste gist.github.com links for larger files -->

##### EXPECTED RESULTS
<!--- Describe what you expected to happen when running the steps above -->
callback works

##### ACTUAL RESULTS
<!--- Describe what actually happened. If possible run with extra verbosity (-vvvv) -->
callback options are ignored
<!--- Paste verbatim command output between quotes -->
```paste below

```

display.debug("RUNNING CLEANUP")
        self.terminate()
        self._final_q.close()
        self._cleanup_processes()
    def _cleanup_processes(self):
        if hasattr(self, '_workers'):
            for attempts_remaining in range(C.WORKER_SHUTDOWN_POLL_COUNT - 1, -1, -1):
                if not any(worker_prc and worker_prc.is_alive() for worker_prc in self._workers):
                    break
                if attempts_remaining:
                    time.sleep(C.WORKER_SHUTDOWN_POLL_DELAY)
                else:
                    display.warning('One or more worker processes are still running and will be terminated.')
            for worker_prc in self._workers:
                if worker_prc and worker_prc.is_alive():
                    try:
                        worker_prc.terminate()
                    except AttributeError:
                        pass
    def clear_failed_hosts(self):
        self._failed_hosts = dict()
    def get_inventory(self):
        return self._inventory
    def get_variable_manager(self):
        return self._variable_manager
    def get_loader(self):
        return self._loader
    def get_workers(self):