Function avif_serialize::serialize_to_vec

pub fn serialize_to_vec(
    color_av1_data: &[u8],
    alpha_av1_data: Option<&[u8]>,
    width: u32,
    height: u32,
    depth_bits: u8
) -> Vec<u8>

See serialize for description. This one makes a Vec instead of using io::Write.