EventSubscriber order of operation

I cannot tell if this is a documentation issue or a code issue, but in testing #2098119: Replace config context system with baked-in locale support and single-event based overrides → I ran into a race condition between two EventSubscribers.

One is a KernelEvent subscriber, the second a ConfigOverrideEvent subscriber.

The second is dependent on the first.

These values "work" for the two subscribers.

// DomainSubscriber
    $events[KernelEvents::REQUEST][] = array('onKernelRequestDomain', 300);
// DomainConfigSubscriber
    $events['config.module.overrides'][] = array('onDomainModuleOverride', 400);

These values do not:

// DomainSubscriber
    $events[KernelEvents::REQUEST][] = array('onKernelRequestDomain', 100);
// DomainConfigSubscriber
    $events['config.module.overrides'][] = array('onDomainModuleOverride', 400);

I have working code and SimpleTests for this in https://github.com/agentrickard/domain