GET /websocket/ HTTP/1.1
Connection: upgrade
Upgrade: websocket
Sec-Websocket-Key: abcde
Sec-Websocket-Version: 1world 2
--MARK--
held 1
--MARK--
hello world 1
--MARK--
hello world 3
--MARK--
hello world 4
--MARK-- world 9
--MARK--
hello world 10
--MARK/--