The base class for the HTTP response handling.Contains methods for setting HTTP response headers, cookies, response status code, writing HTTP response BODY and so on.The most important thing you should know about response — it is Finite State Machine.That means you can do any manipulations with headers, cookies and status code only before prepare() coroutine is called.Once you call prepare() any change of the HTTP header part will raise RuntimeError exception.Any write() call after write_eof() is also forbidden.Parametersstatus (int) – HTTP status code, 200 by default.reason (str) – HTTP reason. If param is None reason will be calculated basing on status parameter. Otherwise pass str with arbitrary status explanation..