This member is added by an implicit conversion from Sec-WebSocket-Accept to
any2stringadd[Sec-WebSocket-Accept] performed by method any2stringadd in scala.Predef.
This member is added by an implicit conversion from Sec-WebSocket-Accept to
StringFormat[Sec-WebSocket-Accept] performed by method StringFormat in scala.Predef.
Confirmation of the server to establish a websocket connection.
SHA1 of concatenation of the (key (as string) with "258EAFA5-E914-47DA-95CA-C5AB0DC85B11)