@Override
    public synchronized void onResourceReady(R resource, GlideAnimation<? super R> glideAnimation) {
        // We might get a null result.
        resultReceived = true;
        this.resource = resource;
        waiter.notifyAll(this);
    }
A callback that should never be invoked directly.
core/src/main/java/com/bumptech/glide/request/RequestFutureTarget.java