Emitted when the server has started reading a new request.
message will be completely blank; not even the Request-Line will have been read yet. About the only thing you can usefully
do with it is connect to its signals.
If the request is read successfully, this will eventually be followed by a request_read signal. If a response is then sent, the request processing will end with a request_finished signal. If a network error occurs, the processing will instead end with request_aborted.
| client |
the client context |
| message |
the new message |