Net::https::nb provides a non-blocking https client. it has the same interface as net::https and net::http, but it will never try multiple reads when the read_response_headers() or read_entity_body() methods are invoked. if read_response_headers() did not see enough data to complete the headers an empty list is returned. if read_entity_body() did not see new entity data in its read the value -1 is returned.