@Override
    public LPProxiedSubject sponge() {
        if (this.spongeSubject == null) {
            this.spongeSubject = ProxyFactory.toSponge(this);
        }
        return this.spongeSubject;
    }
Requests that this subjects data is saved to disk
sponge/src/main/java/me/lucko/luckperms/sponge/service/model/persisted/PersistedSubject.java