@Override
    public synchronized void onLoadFailed(Exception e, Drawable errorDrawable) {
         // We might get a null exception.
        exceptionReceived = true;
        this.exception = e;
        waiter.notifyAll(this);
    }
A callback that should never be invoked directly.
core/src/main/java/com/bumptech/glide/request/RequestFutureTarget.java