bus.yml

services:
    millwright_cqrs.command_bus_proto:
        class: Millwright\CQRSDomain\Bus\Bus
        arguments:
            - []
            - true

    millwright_cqrs.message_bus_proto:
        class: Millwright\CQRSDomain\Bus\Bus
        arguments:
            - []
            - false

    millwright_cqrs.command_bus:
        class: Millwright\CQRSDomain\Bus\BusDefferer
        arguments:
            - @service_container
            - 'millwright_cqrs.command_bus_proto'

    millwright_cqrs.message_bus:
        class: Millwright\CQRSDomain\Bus\BusDefferer
        arguments:
            - @service_container
            - 'millwright_cqrs.message_bus_proto'

BusDefferer.php

<?php

class BusDefferer implements BusInterface
{
    protected $container;
    protected $serviceName;

    public function __construct(ContainerInterface $container, $serviceName)
    {
        $this->container   = $container;
        $this->serviceName = $serviceName;
    }

    /**
     * {@inheritDoc}
     */
    public function handle()
    {
        return call_user_func_array([$this->container->get($this->serviceName), __FUNCTION__], func_get_args());
    }
}