Fix stats responseRecorder Hijacker

Signed-off-by: Emile Vauge <emile@vauge.com>

middlewares/stats.go

@@ -1,11 +1,17 @@
 package middlewares
 
 import (
+	"bufio"
+	"net"
 	"net/http"
 	"sync"
 	"time"
 )
 
+var (
+	_ Stateful = &responseRecorder{}
+)
+
 // StatsRecorder is an optional middleware that records more details statistics
 // about requests and how they are processed. This currently consists of recent
 // requests that have caused errors (4xx and 5xx status codes), making it easy
@@ -51,6 +57,23 @@ func (r *responseRecorder) WriteHeader(status int) {
 	r.statusCode = status
 }
 
+// Hijack hijacks the connection
+func (r *responseRecorder) Hijack() (net.Conn, *bufio.ReadWriter, error) {
+	return r.ResponseWriter.(http.Hijacker).Hijack()
+}
+
+// CloseNotify returns a channel that receives at most a
+// single value (true) when the client connection has gone
+// away.
+func (r *responseRecorder) CloseNotify() <-chan bool {
+	return r.ResponseWriter.(http.CloseNotifier).CloseNotify()
+}
+
+// Flush sends any buffered data to the client.
+func (r *responseRecorder) Flush() {
+	r.ResponseWriter.(http.Flusher).Flush()
+}
+
 // ServeHTTP silently extracts information from the request and response as it
 // is processed. If the response is 4xx or 5xx, add it to the list of 10 most
 // recent errors.