glide rx issue

private void foo() {
    String imageUrl = "https://i1.wp.com/saket.me/wp-content/uploads/2017/08/notification-progress-issue-2.png?w=1200";

    Single
        .<Drawable>create(emitter -> {
          Glide.with(this)
              .load(imageUrl)
              .listener(new RequestListener<Drawable>() {
                @Override
                public boolean onLoadFailed(@Nullable GlideException e, Object model, Target<Drawable> target, boolean isFirstResource) {
                  emitter.onError(e);
                  return false;
                }

                @Override
                public boolean onResourceReady(Drawable resource, Object model, Target<Drawable> target, DataSource dataSource, boolean isFirstResource) {
                  if (emitter.isDisposed()) {
                    Timber.w("Emitter is disposed!");
                  }
                  emitter.onSuccess(resource);
                  return false;
                }
              })
              .into(contentImageView);
        })
        .doOnSubscribe(o -> Timber.i("Subscribed"))
        .doOnDispose(() -> Timber.e("Disposed"))
        .subscribe();
  }