diff --git a/vendor/golang.org/x/net/http2/transport.go b/vendor/golang.org/x/net/http2/transport.go
index aeac7d8..ec18648 100644
--- a/vendor/golang.org/x/net/http2/transport.go
+++ b/vendor/golang.org/x/net/http2/transport.go
@@ -2404,6 +2404,7 @@ func strSliceContains(ss []string, s string) bool {
 
 type erringRoundTripper struct{ err error }
 
+func (rt erringRoundTripper) IsHTTP2ErringRoundtripper() {}
 func (rt erringRoundTripper) RoundTrip(*http.Request) (*http.Response, error) { return nil, rt.err }
 
 // gzipReader wraps a response body so it can lazily