Function cose::util::get_sig_struct_bytes

pub fn get_sig_struct_bytes(
    protected_body_header_serialized: CborType, 
    protected_signature_header_serialized: CborType, 
    payload: &[u8]
) -> Vec<u8>

Sig_structure is a CBOR array:

Sig_structure = [ context : "Signature" / "Signature1" / "CounterSignature", body_protected : empty_or_serialized_map, ? sign_protected : empty_or_serialized_map, external_aad : bstr, payload : bstr ]

In this case, the context is "Signature". There is no external_aad, so this defaults to a zero-length bstr.