Function cose_signature_get_header

pub unsafe extern "C" fn cose_signature_get_header(
    signature: *mut cose_signature_t,
    hdr: *mut cose_hdr_t,
    key: i32,
) -> bool

@brief Retrieve a header from a signature object by key lookup

@param signature The signature object to operate on @param hdr hdr struct to fill @param key The key to look up

@return A header object with matching key @return NULL if there is no header with the key