Function cose_sign_add_signer

pub unsafe extern "C" fn cose_sign_add_signer(
    sign: *mut cose_sign_enc_t,
    signer: *mut cose_signature_t,
    key: *const cose_key_t,
)

cose_sign_add_signer adds a key to the sign struct to sign with

@param sign Sign struct to operate on @param signer Signature struct to add to the sign @param key The key to sign with

@return The index of the allocated sig on success @return negative on failure