Nope, uses Metal directly through the gfx-rs backend.

I see, thanks! What's the preferable approach in Rust, to use Vulkano or gfx-rs (in case you don't need to care about Metal)?

For working directly with Vulkan, ‘ash’ is preferred. If you want to abstract over platforms, then gfx-rs is solid, or wgpu for a higher level api. Vulkano hasn’t really delivered on its promise unfortunately.