pub trait Engine {}

pub trait GpuEngine: Engine {}


pub struct MyEngine {}
impl Engine for MyEngine {}
impl GpuEngine for MyEngine {}


pub struct OtherEngine {}
impl Engine for OtherEngine {}

#[cfg(not(eature = "gpu-engine"))]
pub fn use_engine(engine: impl Engine) {
    // do sth cool with that engine
}

#[cfg(feature = "gpu-engine")]
pub fn use_engine(engine: impl GpuEngine) {
    // do sth cool with that gpu engine
}