Configure a custom SubscriptionRegistry to use for storing subscriptions.
<p><strong>Note</strong> that when a custom PathMatcher is configured via
{@link #setPathMatcher}, if the custom registry is not an instance of
{@link DefaultSubscriptionRegistry}, the provided PathMatcher is not used
and must be configured directly on the custom registry.
Configure a custom SubscriptionRegistry to use for storing subscriptions. <p><strong>Note</strong> that when a custom PathMatcher is configured via {@link #setPathMatcher}, if the custom registry is not an instance of {@link DefaultSubscriptionRegistry}, the provided PathMatcher is not used and must be configured directly on the custom registry.