Send a custom HTTP response to the connection identified by |connection_id|. |response_code| is the HTTP response code sent in the status line (e.g. 200), |content_type| is the response content type sent as the "Content-Type" header (e.g. "text/html"), |content_length| is the expected content length, and |extra_headers| is the map of extra response headers. If |content_length| is >= 0 then the "Content-Length" header will be sent. If |content_length| is 0 then no content is expected and the connection will be closed automatically after the response is sent. If |content_length| is < 0 then no "Content-Length" header will be sent and the client will continue reading until the connection is closed. Use the SendRawData function to send the content, if applicable, and call CloseConnection after all content has been sent.