Function vae_upsample_conv 

pub fn vae_upsample_conv(
    w: &[f32],
    bias: &[f32],
    x: &[f32],
    ic: usize,
    oc: usize,
    h: usize,
    w_img: usize,
    k: usize,
    out: &mut [f32],
) -> bool

Nearest-2× upsample fused with the following conv — the small pre-upsample image is what crosses the CPU boundary.