Function compute_voxel_keys 

pub fn compute_voxel_keys(
    runtime: &WgpuRuntime,
    x: &[f32],
    y: &[f32],
    z: &[f32],
    origin: [f32; 3],
    inv_leaf: f32,
) -> SpatialResult<Vec<(i64, i64, i64)>>

Computes per-point voxel grid keys on the GPU.