in src/utils/eif_signer.rs [309:315]
fn read_and_parse_header(&self, file: &mut File) -> Result<EifHeader, String> {
let mut header_buf = vec![0u8; EifHeader::size()];
file.read_exact(&mut header_buf)
.map_err(|e| format!("Error while reading EIF header: {:?}", e))?;
EifHeader::from_be_bytes(&header_buf).map_err(|e| format!("Error parsing header: {:?}", e))
}