class SerializedSubscriber implements FlowableSubscriber<T>, Subscription {

    @Override
    public void onSubscribe(Subscription s) {
        if (SubscriptionHelper.validate(this.subscription, s)) {
            this.subscription = s;
            actual.onSubscribe(this);
        }
    }

    public  SerializedSubscriber(Subscriber<? super T> actual);
    public  SerializedSubscriber(Subscriber<? super T> actual, boolean delayError);

}