in src/aesgcm.rs [285:292]
fn generate_info(encoding: &str, keypair: &[u8]) -> Result<Vec<u8>> {
let info_str = format!("Content-Encoding: {}\0P-256\0", encoding);
let offset = info_str.len();
let mut info = vec![0u8; offset + keypair.len()];
info[0..offset].copy_from_slice(info_str.as_bytes());
info[offset..offset + ECE_WEBPUSH_AESGCM_KEYPAIR_LENGTH].copy_from_slice(keypair);
Ok(info)
}