subscribe(subscriber, matcher) {
        const metas = this.getAttributeSubscribersMetas(matcher, {exact: true});
        let meta;

        if (metas.length > 0) {
            meta = metas[0];
            if (metas.length > 1) {
                Logger.error("BUG! Found multiple attribute subscribers metas matching exactly. Please report this issue.", this.subscribers);
            }
        } else {
            meta = {
                matcher: matcher,
                subscribers: []
            };
            this.subscribers.push(meta);
        }
        if (!meta.subscribers.includes(subscriber)) {
            meta.subscribers.push(subscriber);
        }
    }
Create a new subscription for attribute changes matching the specified matcher.

@public
@param {import("./AttributeSubscriber")} subscriber
@param {AttributeMatcher|any} matcher