ds3_error * net_process_request(const ds3_client *client, const ds3_request *_request, void *read_user_struct, size_t(*read_handler_func)(void *, size_t, size_t, void *), void *write_user_struct, size_t(*write_handler_func)(void *, size_t, size_t, void *), ds3_string_multimap **return_headers)