The ES backend is the only one which might currently be able to implement this as a no-op.

But as soon as we want to do some message persistance for reliability, or keep dedicated connections open for writes, or try to implement something like HSEARCH-2138 then you will need a signal like this.

So in terms of design I'd rather have the ES backend implement this as a no-op currently, as it's an implementation detail; several other backends would benefit from being able to handle such a signal.