Improve the error message.

staging/src/k8s.io/apiserver/pkg/server/filters/timeout.go

@@ -30,7 +30,7 @@ import (
 	apirequest "k8s.io/apiserver/pkg/endpoints/request"
 )
 
-var errConnKilled = fmt.Errorf("kill connection/stream")
+var errConnKilled = fmt.Errorf("killing connection/stream because serving request timed out and response had been started")
 
 // WithTimeoutForNonLongRunningRequests times out non-long-running requests after the time given by timeout.
 func WithTimeoutForNonLongRunningRequests(handler http.Handler, requestContextMapper apirequest.RequestContextMapper, longRunning apirequest.LongRunningRequestCheck, timeout time.Duration) http.Handler {