(websocketExtension: StringAdd).self
(websocketExtension: StringFormat).self
(websocketExtension: ArrowAssoc[WebsocketExtension]).x
(Since version 2.10.0) Use leftOfArrow
instead
(websocketExtension: Ensuring[WebsocketExtension]).x
(Since version 2.10.0) Use resultOfEnsuring
instead
A websocket extension as defined in http://tools.ietf.org/html/rfc6455#section-4.3