Adding print statements of status collect middleware to stderr

Co-authored-by: Susanne Salzmann <[email protected]>

src/autoscaler/healthendpoint/http_status_collect_middleware.go

@@ -3,6 +3,7 @@ package healthendpoint
 import (
 	"fmt"
 	"net/http"
+	"os"
 )
 
 type HTTPStatusCollectMiddleware struct {
@@ -19,8 +20,9 @@ func (h *HTTPStatusCollectMiddleware) Collect(next http.Handler) http.Handler {
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		h.httpStatusCollector.IncConcurrentHTTPRequest()
 		defer h.httpStatusCollector.DecConcurrentHTTPRequest()
-		fmt.Printf("\n\nCHECKING w\n\n %s \n", w)
-		fmt.Printf("\n\nCHECKING r\n\n %s \n", r)
+		fmt.Fprintf(os.Stderr, "\n\nCHECKING w\n\n %v \n", w)
+		fmt.Fprintf(os.Stderr, "\n\nCHECKING r\n\n %v \n", r)
+		fmt.Fprintf(os.Stderr, "\n\nnext\n\n %v \n", next)
 		next.ServeHTTP(w, r)
 	})
 }