I've been writing some Vulkan code using the rust library [Vulkano](https://github.com/vulkano-rs/vulkano), and came across the following snippet:

```
let compute_pipeline = Arc::new(ComputePipeline::new(
    device.clone(),
    &shader.main_entry_point(),
    &(),
));

```

I'm specifically asking about the 3rd parameter here - in the implementation of `ComputePipeline::new` it is listed as :

```
/// Builds a new `ComputePipeline`.
pub fn new<Cs>(
    device: Arc<Device>,
    shader: &Cs,
    specialization: &Cs::SpecializationConstants,
) -> Result<ComputePipeline<PipelineLayout<Cs::PipelineLayout>>, ComputePipelineCreationError>
where
    Cs::PipelineLayout: Clone,
    Cs: EntryPointAbstract,
{
    ...
}

```

What is the `&()` syntax here? A reference to the unit type?