Merge pull request #67024 from juanvallejo/jvallejo/add-cancel-req-di…

…scovery-rt

Automatic merge from submit-queue (batch tested with PRs 66958, 67024). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

add CancelRequest to discovery round-tripper

**Release note**:
```release-note
NONE
```

Make discovery roundtripper implement the RequestCanceler interface

cc @deads2k

Kubernetes-commit: a945b5d9281ac5cba5e4a2976a0747592c0cff87

discovery/round_tripper.go

@@ -20,6 +20,7 @@ import (
 	"net/http"
 	"path/filepath"
 
+	"github.com/golang/glog"
 	"github.com/gregjones/httpcache"
 	"github.com/gregjones/httpcache/diskcache"
 	"github.com/peterbourgon/diskv"
@@ -47,4 +48,15 @@ func (rt *cacheRoundTripper) RoundTrip(req *http.Request) (*http.Response, error
 	return rt.rt.RoundTrip(req)
 }
 
+func (rt *cacheRoundTripper) CancelRequest(req *http.Request) {
+	type canceler interface {
+		CancelRequest(*http.Request)
+	}
+	if cr, ok := rt.rt.Transport.(canceler); ok {
+		cr.CancelRequest(req)
+	} else {
+		glog.Errorf("CancelRequest not implemented by %T", rt.rt.Transport)
+	}
+}
+
 func (rt *cacheRoundTripper) WrappedRoundTripper() http.RoundTripper { return rt.rt.Transport }